This is a Universe Alteration story in which John and Sherlock meet in a completely different way.

One million thanks to my beta reader and Brit-picker DancingGrimm for this one. It's filled with references to things with which I have little to no direct experience (the London Underground and British health care, mostly), and she really had her work cut out for her this time. Thank you so much, my darling, you are fantastic!

John Watson sighs as he pushes his way into the train carriage. It has been a long, dull day at the clinic, and his leg is bothering him. He's been hoping against hope that the Tube would not be too crowded for him to find a seat, and maybe relax a bit on the ride home. A long shot, he knows, as it is rush hour on a Tuesday and the trains are guaranteed to be packed with commuters. And possessing a limp and a cane certainly doesn't give him any illusions that someone will vacate their seat for him.

He shoulders his way between a businessman in a damp, sad-looking suit and a twenty-something girl with dreadlocks and grabs onto the overhead bar as the train pulls away from the platform, jerking slightly before he manages to brace himself against the jolt of the train's movement. He needs to change his shift, that's all there is to it. Maybe he can talk Sarah into letting him come in and leave an hour later, when the crowds have thinned out a bit.

At the next stop the dreadlocked girl leaves, but more people shove onto the train, packing it even tighter. John closes his eyes and takes a deep breath, gripping the bar above him tightly with one hand and his cane with the other.

A sudden pressure against his back makes him look up. A tall man in a posh suit with dark curly hair has taken the girl's place at the bar behind John, and is being pushed against him by the bulk of people filling the train carriage. He's holding the bar with one hand and facing away from John, who cannot clearly see his face. The edge of his profile shows pale white skin and the hint of one sharp cheekbone.

John gives a mental shrug and turns back around. Can't ride the train at this hour and expect not to be in close contact with your fellow man, after all.

A few more stops, and the pressure against John's back has increased noticeably as more and more people push onto the train. He holds himself rigid, using his cane to brace, and avoids letting the pressure push him against the sweaty businessman in front of him, who seems to have forgotten his deodorant this morning. He is usually able to create a small amount of space in front of him, no matter how crowded the trains get, by using his cane as a barrier. It serves him well today.

As the train moves again, there is a sliding sensation, and suddenly the stranger has turned, his front pressed all along John's back, almost as if they are spooning standing up. John glances sharply over his shoulder, brow furrowed, but the stranger is holding up a mobile directly between their faces with the hand not currently keeping him anchored to the overhead bar, typing something rapidly with one thumb.

After a brief glare, to which the stranger does not respond in the slightest, John turns back around. He wants to massage his leg, but does not have a free hand with which to do so. It is funny how even now, held at such a strange angle for such a long time, the shoulder that actually took a bullet still does not hurt. But his leg, which was never actually injured in the first place, is absolutely killing him.

Two stops before his own, John becomes aware of an increase in the pressure against his hip. Almost as if the stranger is… jabbing him with a blunt object. He shifts, starts to look down, and hears a soft hiss from the man behind him.

And just like that, he knows. He freezes and then jerks his head back up, looking blankly in front of him, eyes wide. It's an erection. The bloke in the posh suit has an erection, and is leaning against John with it, right here on this crowded train carriage.

John is shocked at the warm shiver that thought sends through him.

He holds himself perfectly still, does not jerk away, and keeps his eyes forward, resolutely not looking back at the stranger or around the carriage to see whether anyone has noticed. No one has, he knows. It is too crowded. They probably wouldn't notice if he was actively giving the man a hand job.

Another warm shiver, and he fights the urge to bite his lower lip.

The train jerks to a stop, and the hard bulge is pressed against him more firmly for just a second as the man succumbs to inertia, before he recovers and pulls back to his previous position. John gives in to the urge to bite his lip.

This is ridiculous, and he has no idea what he's doing. He should move away, make some space, maybe move toward the door a bit since his is the next stop. He does not have to make a scene, and chances are good the man is as embarrassed as he is about this. The carriage is packed, after all, and it could very well be an accident. He should just… create some space. But he does not do it.

And although it is entirely likely that it is not for him, that the stranger is thinking of his girlfriend or some other thing, or hell, was even just looking at porn on his mobile (and lord knows John has seen behavior worse than that on the Tube), it still gives him a little thrill to think that it might be. That maybe the stranger finds him attractive, arousing enough that he could not help but get an erection right here in public at the sensation of John's body against his.

It's wrong and a little bit dirty and the most thrilling thing John has experienced in months.

Through the entire short ride between the last stop and his own, John holds himself still and lets the stranger push his erection firmly against him. The man does not move, does not thrust or grind, does not back away, even though a few people exited the train at the last stop and there is slightly more room now.

By the time the train comes to a halt at his stop, John's mouth is watering and he has the beginnings of an erection himself.

John releases his grip on the overhead bar and turns to move toward the door. And, as he does, just for a moment, he deliberately pushes his hip against the stranger's bulge and gives a little twist. Then, without looking back, he marches from the train.

That night, for the first time in months, he does not wake sweating and panting and choking back a scream as a nightmare propels him out of sleep.

-o-o-o-o-o-o-o-o-o-o-

The next day John has to work late, and ends up on the Tube more than an hour later than he usually rides. The carriages are not nearly as crowded, although there is still a good number of people on them, and he manages to get a seat two stops in. He pretends that he is not keeping his eye out for a tall pale bloke with curly hair and sharp cheekbones.

The following day, Thursday, is his day off, and John does not ride the train at all. He limps to Tesco's for groceries, stares blankly at his computer screen, eats beans on toast for every meal, stares blankly at his gun, and watches the telly. When he goes to bed his leg is throbbing and sleep is a long time coming.

Friday evenings are the worst. The Tube is beyond packed when John climbs on, and for a few minutes he thinks he might have to use his cane as a weapon to make people move aside. Eventually he manages to force his way through the press to get a hand onto the overhead bar, squeezed between people on all sides. The discomfort and annoyance of it almost manage to drive all thoughts of the stranger from the last crowded ride out of his mind. After all, what are the odds of seeing him again?

This thought comforts John, who concentrates on ignoring the crush of people and staying upright until he can get off this blasted sardine tin of a train carriage – until the moment, two stops in, when he suddenly feels another body pressing directly against his backside.

His head jerks up and he sucks in a sudden breath, but does not turn around just yet. After all, it could easily be coincidence, just another stranger forced into an uncomfortable position by the Friday night crowds. He tries not to acknowledge the little flutter in his stomach at the idea that it is the same stranger from last time.

John glances over his shoulder. It is him, of course, curly hair, posh suit, cheekbones and all. His gaze is fixed on a point near the front of the carriage, and he does not acknowledge John when he turns around. John turns back, face heating as he blushes. He knows the stranger must be able to see his ears turning red, and the thought makes him blush harder.

This is the first time he's had much of a look at the man, and what he sees startles him. The man is beautiful, in an unusual way, with a long narrow face, full cupid's bow lips, and odd pale eyes. His skin glows like porcelain even in the sickly light of the train. John feels a shiver down the back of his neck as he thinks of the stranger's eyes, looking down at him while he looks away.

Another few minutes, one more stop, and he starts to feel the noticeable push of an erection against his backside. John bites his lip.

After working up his nerve for a bit, John moves his hips minutely, dragging his arse just slightly side to side, still pressing firmly against the stranger's cock.

The response is immediate. He hears a short, chopped off gasp, and the stranger pushes his bulge hard against him. John swallows back his own gasp as a sharp stab of lust lances through him.

The stranger sets a rhythm, thrusting almost imperceptibly against John's buttocks as they ride the crowded train. The change in pressure is slight; from firm to very firm and back, over and over, and each push sends a cascade of heat through John's body. Without thinking he spreads his legs wider, making as much space as he can within the press of bodies on the train, and arches his spine just slightly. Not enough that anyone can tell, oh no, but enough that it changes the angle of his backside, gives the stranger more to push against. He is rewarded by a particularly long hard thrust.

All around them, people are riding the train, going home, going out for a fun evening, going wherever. People are listening to music, looking at their mobiles, conversing, just waiting patiently for their stop. Men, women, families, old people and young people. And right in the middle of all that, John Watson is letting a complete stranger hump him, grind his cock against him over and over, subtle and slight but most definitely happening. Right here on the Tube during rush hour.

By the time they approach his stop, John is hard as a rock and very grateful for the long coat he is wearing, which will allow him to leave the train without giving everyone an eyeful.

John times it carefully, and just as the train jerks to a halt he pushes back against the stranger and rolls his hips, dragging his arse in a slow circle against the man's erection . Then he collects his cane, lifts his chin, and heads for the doors. He does not look back.

His erection is still aching when he gets back to his flat, and he wanks while thinking about the posh stranger, the pressure of his erection against John's arse, the dirty illicit thrill of doing that on the Tube, surrounded by unsuspecting strangers.

He comes all over himself, biting his lip to keep silent as if those strangers might still hear him, and drops almost immediately into a dreamless sleep.

-o-o-o-o-o-o-o-o-o-o-

The next day John works a short shift at the clinic, which closes early on Saturdays. It is typically a busy day, with plenty of scheduled appointments and only one other doctor working. This week it's Denise, whom John does not know well, so he does not feel compelled to make much small talk with her when they see each other in passing. John usually likes the pace of the Saturday shift, which keeps him too busy to spend much time dwelling. That is one of the reasons he volunteers to do it every week instead of rotating like the other doctors; the other is that, unlike the other doctors, John does not have any family or friends with whom to make plans during the weekends, so he figures he might as well take the shift and let everyone else off to enjoy themselves with their loved ones.

This week, the frantic pace of the Saturday shift does almost nothing to distract John from freaking out over what he did on the Tube last night. He cannot believe he did it, let a total stranger grind on him, tolerated and even encouraged it. He cannot imagine what possessed him to do something like that.

Just thinking about it makes him hard.

When he gets home that afternoon, he wanks again to the memory, the thought of a strange man on the Tube using him for pleasure, completely anonymous. His orgasm hits him like a freight train.

Sunday is another long, dull day off. John does his laundry, takes a walk through Regent's Park, cleans his bathroom, and wanks twice. When he goes to bed, sleep is not as hard to find as it sometimes is.

Monday comes, and John works his typical shift. He does not follow through on his plan to ask Sarah if he can change his hours. He tries not to think about why.

When he climbs onto the train that evening, he is careful to board the same carriage that he rode on Friday, second one from the end of the train. He squeezes in and takes his typical position standing up, holding the bar with one hand and bracing himself on his cane with the other. He faces toward the front of the train, as usual, and carefully does not look around as the train starts moving. He tries not to get his hopes up, and wills his heartbeat to slow down.

The odds of the same man just happening to choose the same carriage as him a third time are very slim. And although John tends to ride at the same time every day, not everyone's schedule is so regular. He might be on a later train, or have already taken an earlier one. And even if he is here, he might not be interested in…

Before he can finish the thought, he feels a body press against his, erection already very much present and rubbing against his arse. His eyes flick upwards and he sees a now-familiar arm holding the bar just behind him, black leather glove and thick black wool coat concealing every part of the stranger's skin.

The stranger does not hesitate this time, immediately starting the slight thrusting motion that he used last time, erect cock pushing over and over against the flesh of John's arse. John is instantly hard.

At the next stop, more people crowd onto the train. A man, clearly a young professional sort in a suit and tie, messenger bag over one shoulder, squeezes toward where John and his stranger are standing, already raising his hand toward the bar. John realizes with a start that he means to grab the bar between them, and without thinking he presses himself backwards, his whole body flush against the stranger. The young man grabs the bar in front of John instead.

As soon as he moves he realizes what he's done, and he can feel himself blush scarlet. But then, before he can do anything else, a leather-clad hand settles on his hip, holding him in place.

As the train pulls away, the man resumes thrusting oh so slightly against John. The hand on his hip squeezes rhythmically in time to the thrusts, anchoring John in place, giving the man leverage to push harder. John has to fight the urge to moan at the onslaught of lust he feels as the stranger grinds against him as they ride the crowded train.

Several stops later, John's cock is hard and throbbing in time to the stranger's steady, relentless rhythm. Then he feels something, a gentle brush against the back of his head, followed by a hot wet exhalation of breath down the back of his neck.

The sensation sends electricity crackling through John's body, lighting up his nerves like fireworks, and he gasps out loud. The stranger's hand squeezes hard on his hip and he pulls himself tight against John's arse, a long constant push, and then rocks slightly from side to side as he exhales against John's neck again, and then again. The muscles of John's abdomen twitch with each breath, and he knows the stranger can feel it.

As John's stop approaches, the stranger moves back slightly, just enough to reduce the pressure. John swallows, trying to ignore the way his stomach swoops in disappointment as the train slows down.

The train stops. Before John can do anything, before he can move, the stranger's other hand drops from the bar and he grabs hold of John's other hip. Pulling John back against him with his grip, he dips just slightly, pushes his cock hard against the underside of John's arse and very deliberately rubs it up the cleft with enough force that John feel his cheeks part slightly. John lets out a soft, high-pitched whine before he can stop himself.

Then the stranger drops his hands and moves back, completely breaking contact. John's knees feel weak, and he has to wait for a short moment before he manages to leave the train without wobbling all over the place.

When he gets home, he barely manages to open his trousers and get a hand on himself before he is coming, replaying the feel of the stranger's grip on his hips, the pressure of his cock, that last thrust dragging against the tender skin in the cleft of his arse.

-o-o-o-o-o-o-o-o-o-o-

Tuesday evening. John's stomach is filled with butterflies as he waits for the train to arrive. He glances surreptitiously around the platform, looking for a tall figure with a mess of curly hair. Does not see one.

The train pulls to a stop, doors opening to let one pack of commuters push their way out of the train in time for another to surge on board. John is one of the first onto the train this time, having carefully chosen his position just in front of the spot where he knows the door to the second carriage from the end will be.

He squeezes through the doors and looks up. Standing almost right in front of him, holding on to the overheard bar with one gloved hand and casually texting with the other, is his stranger. The man does not acknowledge him.

John swallows. He has no time to think, to consider, as other people are shoving him from behind, trying to get onto the train before the doors slide shut. He has to make an instant decision.

He moves over to the bar and pushes himself between the stranger and the pretty woman in front of him, facing away. It's a tight fit, but there is some space. The woman gives John a glance over her shoulder and scoots even further forward.

As soon as he gets a grip on the overhead bar, the stranger's hand is resting on his hip and a familiar bulge is pressing against his arse. By the time the doors slide shut and the train pulls away from the station, the stranger is already grinding against him, and John's erection is full and throbbing. He cannot stop the smile from rising to his face.

After a few moments John works up his courage and starts rolling his hips, just slightly, just a tiny bit. He is confident that none of the people around them notice their motions in the crowded carriage, the steady forward press of the stranger and now his own gentle up-and-down, but just to be safe he makes a bit more space in front of himself with his cane.

The stranger lets out a quiet hum at this, the sound deep and rumbling, and John thinks he can feel it in his bones as much as he can hear it. He sucks in a fast breath as lust shoots through him, and the stranger leans forward, pressing harder against his arse and breathing down the back of his neck. John only just swallows back the moan that tries to escape his lips.

The woman in front of him shifts backward, bumping into John's cane with her hip, and then gives him a glance of apology. John drops his eyes, unable to stop the rush of blood to his face as he meets the gaze of one complete stranger while he is secretly letting another hump his arse. He is reminded, suddenly and all at once, that they are in public, on a crowded train, that he and this man are doing this while surrounded by completely oblivious people, people who would likely be shocked and horrified if they saw.

The thought sends arousal through his body, a heady combination of desire and shame that makes his face heat and his cock pulse. He rolls his hips harder, bites his lip.

The stranger's hand slides around the front of his hip, moving slowly toward his groin, and John freezes.

As soon as he goes still the hand stops moving, but stays in place resting just over the crease of his thigh. The stranger exhales a long slow breath down the back of John's neck and gives a little nudge with his own erection. John shudders.

Then, slowly and deliberately, he rocks his hips against the stranger once more.

Instantly, the hand finishes its journey, dipping under the hem of his coat and coming to rest directly over his straining erection. Without hesitation, the stranger drags his fingers up and down the length of it with firm pressure. John's head falls forward, eyes closing automatically, and he bites his lip almost hard enough to break the skin as pleasure jolts through him.

The stranger sets a rhythm, squeezing John's cock through his trousers, rubbing his thumb back and forth across the head, all the while thrusting his own erection against John's arse and panting down the back of his neck. John cannot react, can do nothing except stand with his head bowed, breathing hard through his nose and biting his lip to hold back the moans.

Every time the train stops and the doors open, John is certain they are going to get caught. They are almost directly in front of the door. Surely, despite how crowded the train is, someone will see, see this stranger's hand gripping his cock, see the slight thrusts the man is making against his backside. And each time, the thought pushes him higher, embarrassment making his pleasure sweeter, more intense. He is climbing, climbing…

At the next stop, the stranger's hand drops away and he steps back completely, creating a small gap between their bodies. John's eyes fly open and he looks around in surprise, almost turning to face the man before he becomes aware that they are at his stop. He barely manages to collect himself and get off the train before the doors close.

As he steps off, he cannot help but look around. No one is obviously reacting, avoiding his gaze or smirking. Apparently, no one noticed.

When the train starts to pull away, John turns and glances through the window. The stranger is looking back at him, and as their eyes meet for the first time, John feels a jolt pass through him, another wave of lust stabbing through his body. Just before the train drags him out of John's sight, the man smiles.

When John gets home that night, he lies on his bed and grabs hold of his erection through his trousers. He copies the movements the stranger used, picturing himself still on the train, still being groped by a total stranger while surrounded by people. In his mind, the people see. They talk, point, giggle, and John can do nothing but stand there and let the man fondle his cock. He hears whispered words, slut and whore and slag, and he moans out loud. Someone laughs, and he pictures the disdainful expression on the stranger's face as he gasps for more.

John comes in his pants, and comes, and comes, still squeezing himself through his trousers.

-o-o-o-o-o-o-o-o-o-o-

The following day, the stranger is not waiting when John boards the train. He tries not to feel disappointed when he squeezes on, looking around but not seeing a head of curly hair, a heavy dark coat. He feels disappointed anyway.

Repeatedly during the trip home John is bumped, jostled, pushed against. Each time he glances around, heart pounding, and each time experiences that sickening swoop in his stomach when he sees that it is not him, not the stranger John wants, hopes to see.

By the time he gets to his stop and climbs off the train, his erection, which had popped up at the mere sight of the Tube station in some sort of conditioned Pavlovian response, is well and truly gone. John watches the train pull away, peering in the windows as they fly past, looking for a familiar silhouette, but does not spot one.

He limps home, leaning heavily on his cane, and tries not to think about it.

The next day is his day off, and he spends the day actively avoiding thinking about it, and mostly failing. He waffles between the conviction that his little train fling is over and the idea that missing one day does not mean the man will never be there again. Maybe he had to work late, or maybe it was his day off as well. John was not on the train last Wednesday, so maybe the man was not expecting him. Or maybe he had got what he wanted from their… association, and John would never see him again.

When he catches his thoughts heading down this path, he distracts himself with chores, doing a thorough clean on both his kitchen and his bathroom, scrubbing until the tile surfaces glisten, until the tub and toilet are so clean you could eat off them.

The day passes faster than most, and John falls asleep, exhausted, almost as soon as his head hits the pillow.

Friday is cold, a light dusting of snow coating the ground as John stumps down the stairs to the Underground. He is bundled up in his thick winter parka, as are most people waiting for the train. John takes his position near the end of the platform, heart in his throat as he waits for the train to arrive.

The train pulls up, stops, and the doors slide open. John scans the space as he pushes forward with the other commuters, but all he can see is a wall of puffy coats and knit hats. He shoves his way down the train, feeling more claustrophobic than ever on a Friday night with everyone in their heavy winter gear, until he finds a space where he can grab the bar. He keeps the lid on his disappointment, reminds himself that it was a long shot anyway.

Just after the train pulls away from the Tube station, there is a sudden sensation of very deliberate pressure against his back.

Before he can turn around, he feels a puff of warm breath against his cheek, and a voice speaks directly into his ear.

"I think, this time, I'm going to make you come right here on the train."

The voice is deep, smooth, like muffled thunder wrapped in melted chocolate, like sex itself. John feels his mouth fall open, suddenly gasping as if all the air has been sucked out of the space. His cock gets hard so fast his vision goes grey.

The hand settles on his hip as the stranger pushes against him, slowly, emphatically, hard cock grinding into his arse. John gasps again before he can catch his breath, and then arches back into the pressure.

The stranger chuckles, and then his hand slides down from John's hip, dipping low for a moment to get beneath the hem of his parka and then back up to rest on his flies, directly over his hard cock. Fingers trace the shape of it with gentle pressure, softly running up and down the length. John wants to moan but stops himself.

He darts a glance around, but no one has noticed anything. The weather is working in their favor, John realizes. The abundance of thick heavy coats reduces visibility even further than usual, making it almost impossible to see anything below the level of people's shoulders. The bulk conceals motions, making it easier to move undetected, allowing greater range. And the usual sounds of the Tube are joined by the constant susurrus of crinkle and scrape from so many people shifting around in their stiff outerwear.

The stranger's hand squeezes his cock suddenly, and John's head falls forward. He bites his lip, letting the pleasure break over him in waves as the stranger works his cock and grinds against him, pushing hard, dragging his erection up and down the curve of John's arse in a motion feels like it should be obvious even despite the concealment of puffy winter coats.

If John pays attention, he can clearly pick out the rhythmic shush shush shush of the stranger's trousers dragging against his, almost but not quite covered by the sounds of the train, of people moving around them.

The thought of how obvious they are being sends a rush of heat to John's face and makes his cock twitch and pulse in the stranger's grip. He squeezes his eyes shut and starts to thrust in tiny motions forward and backward between the stranger's hand and his cock. Hot breath pulses against his ear, the side of his neck.

It feels so good, the steady firm strokes on his cock through his trousers, the sensation of the stranger's arousal hard against his arse, the warm moisture against his skin, the knowledge that they are doing this in public, surrounded by people. John opens his mouth to pant, pleasure rolling through him.

"Lift your head. Look up."

The stranger's deep voice resonates in his ear, quiet and commanding. Without realizing he is going to do it, John straightens his neck and opens his eyes.

"Good." Delicious pressure as the stranger swirls his thumb over the head of John's cock. "Do you see that woman? Right over there?"

John struggles to focus, but after a moment he sees a middle-aged woman, standing just a few feet ahead of them. She is separated from them by several coat-swaddled bodies, but unlike most passengers she has taken a position facing away from the front of the train, which means she is facing almost directly toward them. As John looks up she lifts her eyes from something in her hand, and John looks away quickly before they can make eye contact. The stranger's hand squeezes tight on his cock.

"She keeps glancing over here," that voice comes again, dripping into his senses like honey. "I think she can see, can tell what we're doing."

"Oh," John gasps, the stranger's words sending a sudden stab of lust through him. His balls tighten up so fast that it is almost painful. "Oh God."

"She's looking at us right now."

John squeezes his eyes shut again and drops his head, heat flooding his face. He draws a shaking, ragged breath.

The stranger ruts harder against John's arse, rubs faster on his cock. "What must she think of you?" he purrs.

"Oh fuck," John whispers, broken, and then he is coming. Coming right there on the train, during rush hour, in his trousers. He clenches his jaw tight, holds back the moans and words that want to spill from his lips, and shakes through it silently, grateful for the support of his cane keeping him upright.

Behind him, the stranger lets out a pleased hum. He holds John firmly through his orgasm, letting his hand fall away once the aftershocks subside and John starts to come back to himself.

"Good boy," he says in his deep, sinful voice as he drops his hand. John shudders.

He wants to look up, look to see if that woman saw what happened, if anyone else did, but he cannot. He is more embarrassed than he has ever been. And that may have been the best orgasm of his life.

"The next stop is yours," the stranger says after a moment, erection still pressed against John's backside. John manages to nod, face still turned down, eyes still shut.

When the train stops, John stumps away, limbs shaking, relying heavily on his cane. He keeps his face turned down, does not make eye contact with anyone as he disembarks. He does not turn when the train pulls away.

He feels… blank. Empty. Not bad, not good. Just… nothing.

He goes home and does not think about it. He takes a shower and does not think about it. He eats dinner and does not think about it. He watches telly and does not think about it. He goes to bed and does not think about it.

He has less trouble falling asleep than he expects.

-o-o-o-o-o-o-o-o-o-o-

When he wakes up Saturday morning, John is instantly panicking.

What the hell had he done? What the fuck was he thinking? He let some stranger give him a hand job on the Tube! During rush hour! In front of everyone! And at least one person had seen, hadn't she? Christ, he was shocked he didn't end up with an ASBO.

He ruthlessly ignores the thought that he enjoyed it more than he has enjoyed absolutely anything since he got invalided out of the army. He also ignores the beginning of an erection that starts to develop as he is mentally reviewing all the reasons it was wrong.

That's it, this needs to stop.

Starting Monday, he is going to change the time he rides the train. Even if Sarah does not let him switch shifts, he could just stay late at the clinic. Or maybe get something to eat before heading home. Whatever. The important detail is that he will no longer ride the train at rush hour, where he might encounter that particular stranger.

Having made this resolution, John does not find himself feeling better. If anything, he feels worse, which is confusing. He scrapes himself together and goes to work, hoping to distract himself.

He ignores the rush of adrenaline he feels as soon as he steps onto the train platform at the Underground station.

John floats through his day, feeling disconnected and distracted. He is lucky that Saturday is a short day, because he is not sure he could have coped with a typical day. The other doctor on shift, Pete, is someone with whom John is usually friendly, but he does not have it in him to make conversation today. Pete comments several times that John does not seem well, and maybe should go home early.

John does not tell him that going home is the last thing he wants to do.

When the clinic closes, John heads out to take a walk. He does not have a destination in mind; he just knows he needs to be moving instead of sitting still.

He finds himself drawn inevitably onto the Tube, stamping down the stairs to the station near the park before he even consciously realizes he has decided to go. He boards the first train that pulls in without even looking where it is going.

On Saturdays the Tube is filled with tourists holding maps and looking at the different colored Underground lines, whispering to each other, cameras dangling from straps around their necks. John has no trouble getting a seat.

He rides the trains for the rest of the day, exiting at random stations to switch lines, going nowhere in particular. He barely notices time passing as he watches the people around him, the tourists and the locals, the young and the old, the average and the bizarre. Eventually, he realizes that the crowds have thinned out, the few people who are boarding often wearing heavy coats, and he glances at the time on his mobile. It is late evening, well after the time he usually eats dinner. He wonders why he is not hungry.

John looks at the map and realizes that he is a good distance away from his flat. He will have to transfer twice to even get back on his own line. He shrugs to himself and sits forward in his chair, waiting for the right station.

When John steps off the train, the platform is nearly deserted. He shuffles carefully through the station to get to the correct platform, which is equally bare. The lights in the station are cold and stuttering, bathing the cement floor in a strange glow and making John's skin look yellow and pallid.

The train pulls up and the doors slide open. John steps through.

The carriage is nearly empty. Toward the front John can see two women, seated side by side, heads held close together as they talk, bags gathered at their feet. A single man, apparently asleep in a seat with a newspaper over his face. He turns to glance the other direction and sees…

Oh shit.

The stranger. He is standing with his back to John, apparently peering intently through the window in the door at the back of the carriage, but John instantly recognizes his wild curls, his height, his long black coat.

John knows he should step back before the man turns, let the doors close, catch the next train. But he is frozen, locked in place like a deer hypnotized by the headlights of an oncoming car. He stares, does not move.

The doors slide closed, and the train pulls away. The man starts to turn, and still John stands, braced on his cane, watching it happen in slow motion.

The man completes his turn, spots John immediately. Their eyes meet. The man smiles.

"Well, isn't this convenient," he says, his voice louder, more clipped than the last time John heard it, but just as deep and mesmerizing. He stalks down the aisle toward John, moving with more grace than anyone should be capable of on a moving train. John still cannot move.

"I… I don't…"

"Hush," the man says. He walks directly up to John, grabs the front of his coat with both hands, and spins him around. John loses his balance and collapses backward onto the firm bench seat lining one wall, cane falling out of his hand and rattling hard against the seat beside him before falling to the floor of the train.

"What-" is all John manages to say before the man climbs onto his lap, straddling him. His huge coat falls over them like a blanket. John turns his face up, and then he is looking into the stranger's gimlet eyes from only a few inches away. The words die in his throat.

"I'm on a case and I don't want the suspect to notice me. I need a diversion, and you'll do nicely."

"What?" John manages again, and then the stranger is leaning forward, breathing heavy into his ear. John's cock stirs, and without thinking about it he brings his hands up to rest on the stranger's waist

"My name is Sherlock Holmes. And you are?" the stranger purrs into John's ear, voice slow and sweet. John's mind struggles with the question as he shivers, hands clenching convulsively on the man's hips.

"I… uh… John. John Watson." His voice is rough, broken. He does not remember when he closed his eyes.

"Well, John Watson, I am a consulting detective and I'm currently investigating a human trafficking ring." As he speaks, the stranger – Sherlock – is running the tip of his nose up and down the length of John's neck. John throws his head back; his entire body is covered in gooseflesh. "My main suspect is in the last carriage on this train and he should be coming through here in about… six stops, to meet up with his connection in the first carriage. I don't want him to notice me. Can you help me look busy?" And he nips John's throat.

"Oh… um… okay," John manages, his entire focus centered on the feeling of the other man's lips on his neck. He is not sure what he just agreed to, but he barely cares.

"Very good," the man murmurs against his skin, and then he licks a stripe up John's neck. John gasps, squeezing hard on the man's hips, and Sherlock drops his weight down, bringing their erections into abrupt contact.

John cannot help it, and he moans out loud at the sudden sensation of another hard cock against his own. It's been so long, so long, and fucking Christ but it feels good. He slides his hands around to clutch at Sherlock's arse and grinds them together.

"Mmmm, yes," Sherlock rumbles, mouth coming up to tongue at John's ear, the line of his jaw. John's mouth waters as those lips slide closer to his.

Sherlock leans back just enough that John can see his face, rolling his hips back and forth in a steady rhythm, dragging his clothed cock back and forth against John's. His eyes are trained on John's mouth, and John licks his lips. Sherlock mirrors the motion, and then his eyes flick up to John's for just a second before he leans in, bringing their lips together.

The kiss is slow and hot, a wet drag of lips and tongue sliding together in a sensual glide; intense but relaxed, in direct counterpoint to the increasingly frantic motion of John's hips, the desperate little grunts he is making in the back of his throat.

Faintly, John is aware of the train jerking to a halt and then moving again. He ignores it, barely aware of anything outside the feel of Sherlock's lips on his.

Finally, the kiss breaks, and John sucks in a deep lungful of cool air before letting it out in another long moan. Above him, Sherlock smiles and licks his lips.

"They can hear you, you know," he says, voice sly. And all at once John remembers that they are on a train, in a carriage with several other people, all of whom can see Sherlock straddling his lap, hear him moaning. His face flushes bright red and his hips jump up involuntarily.

"Shit," he says, barely keeping back another moan. Sherlock chuckles.

"They can't see, not really. My coat is covering us. But they can hear, and they certainly know what we're doing." That voice is liquid sin, rolling over John's skin.

He stills, tries to push himself up straighter in the seat. This is wrong; it has to stop. He has to get control of himself. But Sherlock braces his hands above John's shoulders and holds him down, grinding against his erection.

"I know you like it," he whispers in John's ear. "So do I." And John's legs abruptly give out as he collapses back against the seat.

That mouth latches onto John's neck and sucks, and John bucks up against Sherlock shamelessly as waves of pleasure roll through him. He is so lost to it that for a moment he does not realize that Sherlock's hands are between them, working at his groin.

He hears the sound of a zip, but it takes him a moment to realize what it means. Then he feels the pressure against his groin change and gathers the presence of mind to look down. What he sees are Sherlock's hands drawing down his fly zip, and Sherlock's cock, bare and leaking, already jutting out from the open flies of his own trousers.

A blast of adrenaline slams through John, kicking up his heart rate. He sucks in a shocked breath and lurches again, trying to sit up, but Sherlock's weight pins him in place.

"What are you-" he starts, but then Sherlock gets John's trousers open and reaches in, pulling his cock out through the flap in his boxers, and he loses the ability to speak.

"Shh," Sherlock says unnecessarily, smiling wickedly as he stares into John's wide open eyes. He raises his hand and spits onto his palm without breaking eye contact, and John feels a shock of lust rock him at the sight of it. Then Sherlock leans in, pushing their bare cocks together, and wraps his hand around both of them.

John's mind goes blank. He thrusts up into Sherlock's fist, feeling the drag of his erection against another, the wet slide of Sherlock's hand. He thinks he might be grunting, whimpering, but he cannot stop himself.

Over him, Sherlock hunches forward until his mouth is just above John's ear, thrusting into his own fist in counterpoint to John's rhythm, panting. He is letting out quiet little hums and sighs directly into John's ear. Each one shivers through him, devastating and arousing.

Sherlock lips at his ear lobe, twirls his tongue around the shell of John's ear, inhales around the wet skin. The sudden cold makes John hiss, cock throbbing.

"Can you hear that? The sound of my hand on us?" Sherlock asks, voice deep and dark as midnight. John listens, and yes, he can hear it, the steady wet slap and slip as Sherlock works their cocks. "I wonder who else can hear it."

"Oh, oh God," John says, as he imagines the other people on the train listening to this, seeing them so clearly humping each other right here in front of everyone. His cock twitches in Sherlock's grip.

"They know what we're doing, what you're letting me do to you."

"Yes, oh!" John grunts, thrusting faster, feeling his orgasm start to gather low in his belly.

"Right here, where anyone can see," Sherlock says, and John feels his other hand close over the heads of both their cocks, circling around the sensitive flesh with sublime pressure. "Anyone can hear you moaning, hear how much you love it."

John's orgasm hits him like a blow to the spine, pleasure slamming through him so fast and hard that he cannot move, cannot make a sound. He curls forward, eyes squeezed tight and mouth open in a silent scream, and pushes his face against the warm woolen shoulder of Sherlock's coat as he comes and comes. Dimly, he hears Sherlock gasping and feels him jerk above him.

When the intense pleasure finally ebbs, John finds himself panting, nuzzling against the side of Sherlock's neck, gripping the lapels of his coat with both hands. Sherlock is leaning over him, still softly squeezing their cocks with one hand.

With a final deep breath, John uncurls himself and leans back. His stomach muscles twitch from the extended clench as he rests himself backward against the hard plastic train seat. Blushing, still awash with pleasure, he meets Sherlock's eyes. Sherlock looks as wrecked as John feels, and as their eyes meet, he smiles.

"Made a bit of a mess." His eyes flick down to his hands and back up again. John follows his gaze and sees that Sherlock has managed to catch most of their semen in one hand, although some has leaked out to land in white drips around the flies of John's trousers.

Sherlock moves his hands away from their spent, softening cocks, cupping the one to keep from spilling come everywhere. He looks at John again and his smile turns wicked; John feels his pulse jump at the mere sight of it. Then Sherlock brings the hand to his mouth and, without breaking eye contact, licks the gob of white liquid from his palm.

John bites his lip.

Sherlock lowers his hand to John's mouth, which falls open without a conscious thought from John, and pushes in his fingers, one after another. John sucks each one clean, his eyes never leaving Sherlock's.

Then Sherlock leans forward, and they are kissing again, tasting themselves on one another's lips. The kiss is hard, deep, soul-searing, and John arches up against Sherlock, burying both his hands in that great mass of curly hair.

It goes on forever, or possibly only for a few minutes, and when they finally break apart John is breathing heavy again.

Sherlock leans back on his knees, taking his weight off John's legs.

"Better get yourself straightened up. That was him. We need to go," he says.

John blinks at him, baffled. "What?"

"The suspect. You provided an excellent diversion, by the way. He didn't pay us any attention when he passed." Sherlock is tucking himself away as he talks, zipping his trousers and straightening his shirt. John follows suit quickly, feeling suddenly adrift.

"I don't…" he starts, but he cannot think how to finish.

"Oh, come on, don't be an idiot. Human trafficking ring, remember? The suspect just walked through, on his way to meet his contact. We have to follow him." Sherlock's voice is fast, his words clipped, and he sounds supremely annoyed. He climbs backward off John's lap, adjusts his clothing.

"'We?'"

"Yes, 'we.' Having a doctor with military experience along will be very useful to me." He pauses and looks John up and down with a haughty expression. "And don't pretend you aren't looking for some excitement in your life, because we both know better."

John has no idea how Sherlock, still a total stranger for all that they've just had sex on the Underground, knows about his profession, his military history. He should be upset, possibly afraid. And the man's arrogant assumptions, his supercilious tone; from anyone else, John is certain that he would be offended, angry. But for some reason, coming from this man he only finds it amusing. He feels himself start to smile as he hops lightly to his feet.

Sherlock looks up from where he is adjusting his gloves, takes in John's stance, his smile, and grins back. Then he catches John's chin in one hand and leans in close.

"And maybe, once we've caught him, we can find a way to celebrate." John feels his eyes widen at the slow sultry drag of Sherlock's voice, and licks his lips. Sherlock grins wider as he drops his hand. Then he spins on his heel, coat flaring out dramatically, and takes off toward the front of the train carriage. "Now, come on, John!"

And John runs behind him, paying no attention at all to the man still sleeping beneath his newspaper, the giggling women sitting at the front of the carriage who stare as he runs by. He just follows Sherlock, feeling really, truly alive for the first time since he got back from Afghanistan.

Behind them, John's cane lies on the floor beneath the bench seat, forgotten.

This story came to me in my sleep. Literally, I had never conceived of any part of it at all and then one evening I went to bed, absentmindedly fantasizing about gay sex (as you do), and woke up the next morning with this entire story fully formed in my head. I wrote it down across about three days, and then my lovely friend DancingGrimm and I spent the next month making it presentable. Hope you enjoyed! I had a blast writing it.