The Mayo Clinic prescription for hypothermia is this: Tea. Blanket fort. Sex.

All right, it doesn't come right out and say that on the website. But Sherlock can read between the lines.

He peers at the text on the screen. "If the affected person is alert and able to swallow, provide a warm, nonalcoholic, noncaffeinated beverage to help warm the body." John does not drink warm, nonalcoholic, noncaffeinated beverages, but two out of three ought to work.

"John? Do we have any wassail left?"

Wassail is noncaffeinated. It's also warm when microwaved. Sherlock makes a mental note: Must clear out eyeballs.

John is dripping all over the sofa. "B-b-buggering, f-f-f-ucking, buggery fuck," he gasps, trying to divest himself of his heavy, soaking boots.

Ah. Out of wassail, due to the events of last night. Substitute: tea. Look forward to John's blog entry on Lestrade's visit: "The Case of Who the Hell Drinks That Much Mulled Punch?"

Sherlock turns his head back to the screen and continues reading. He rather likes having this computer. Technically, it's John's computer, but the John in question is his John, and everything is transitive.

According to the website, the next phase in restoring one's hypothermic flatmate to health after being partly – all right, entirely – responsible for him plunging into a half-frozen lake whilst pulling rugby moves on a serial strangler is this: "Be gentle."

Thinking of the last time he heard that phrase, Sherlock bites his lower lip. The temperature in the room feels like it's just gone up two degrees. Any hotter, and he's going to have to undo another button on his already precariously fastened shirt.

Sensing a change in the air, John lets go of his own booted foot and puts his stream of profanity on pause. "Is th-th-that my computer?"

Sherlock is not at all concerned by the threat in his voice. John is shivering much too hard to hurt him. "Mine, John. Set theory wills it."

"You'd b-b-best not be looking at anything illegal on my machine."

Oh, God. "Be gentle." John said that the day after he slid down that gravelly embankment to the Thames on his arse. I was celebrating his participation in the capture of the Beast of Belgravia by fucking him in the shower.

"'When you're helping a person with hypothermia, handle him or her gently,'" mutters Sherlock, his eyes glazing over.

John regards him with suspicion. The three vertical wrinkles on the bridge of his nose are deployed to the utmost.

"What are you reading?" he wants to know. "Why are your pupils like that?"

His teeth have stopped chattering. He must be warming up. Probably as a sympathetic response to my own increase in body heat.

"Science," says Sherlock.

John groans and returns to clawing at his boot with frozen hands. "You do realise you're a Thomas Dolby video come to life?"

"Mmm." Sherlock has no idea what John is talking about. His responding hum is meant to sound neutral, not sultry, but his voice does not cooperate.

While "be gentle" is obviously a directive to initiate sexual activity, the reference to handling implies that the activity need not be intercourse. Masturbation of the afflicted person would also meet conditions necessary for health.

Sherlock wonders whether he is perhaps misinterpreting the advice. He stops wondering when he gets to the directive about "remove wet clothing."

He attracts his flatmate's attention with a husky cough. "I think you should take off that jumper," he says.

"Listen, you imbecile. I can't even take off these boots. They've frozen solid to the ends of my feet."

Sherlock frowns and consults the site. "Cut away clothing if necessary to avoid excessive movement," it says.

Good God.

The amateur medical consultant lets out a huff of air. Although scissor play has not been part of their bedroom repertoire to date, Sherlock is willing to try anything if it will help John, who, as it happens, is still flailing about in a medically inadvisable way. Tying him to the furniture would also prevent excessive movement, but the website doesn't require it. Yet.

"You know, a little help would be appreciated," says the man struggling on the couch.

"I'm helping," says Sherlock. He checks the site for one last tip and finds this: "To warm the person's body, remove your clothing and lie next to the person, making skin-to-skin contact. Then cover both of your bodies with blankets."

Sherlock finds the huff of air he recently expelled and sucks it back in.

The treatment plan laid out by the clinic is clear. It doesn't take a vocabulary as formidable as Sherlock's to see that the idea is to take off the afflicted man's clothes, construct a blanket fort large enough for both of them, then strip himself and mate with John in the blanket bower. Gently.

A marriage certificate issued by the City of London could not grant him more sexual license than this medical website, with all its Kama Sutra specificity, has done.

Very well, thinks Sherlock. Tonight's game is "Bring John back to health after causing him to fall into the Regent's Park boating lake in the name of public justice."

The Game is On.

John looks down. His mad, beautiful, dark-haired boyfriend is currently on his knees in front of him, licking his lips.

"The fuck?" says John.

"All right," says Sherlock. His eyes are hopeful.

Still booted, John sticks his hands into his own armpits to see if that will warm them. It doesn't. "What? No. It's a figure of speech, you daft git. It's not an invitation to a date."

"Pity."

"Look, I know you want a post-case shag, but it's not on. The only way I would have an erection right now would be if I already had one when I fell into the lake and it froze that way."

"Did it?"

John groans. "No. For God's sake, Sherlock, call it off."

Sherlock takes a clammy boot in both hands, applies the optimal amount of torque, and whisks it away from his flatmate's frozen foot. "Call what off?" he asks, unperturbed.

"Not to put too fine a point on it: your dick. There is no way you are getting a leg over tonight. Neither are you getting a leg under or around. I am getting dried off, I am going to bed, and if you are very lucky, I will be too tired to murder you in your sleep."

"I'm not sleepy," Sherlock observes. He peers up at John through long, dry lashes.

"Dry" is a bit of sore spot for John at the moment. "Lucky you," he mutters, shivering.

Sherlock rubs John's wet, besocked foot, insinuating his clever fingers into the pressure points. John gives a helpless moan.

"This is what you do, isn't it?" John wants to know. "You look for holes in me and then insert yourself into all of them."

"John. What a beautiful image."

With a wry smile, Sherlock tilts his head up towards his flatmate. John can't help but notice how his fine, slender neck catches the light from the nearby lamp. The pronounced hollow at the base of his throat, which John has always found jaw-droppingly erotic, is plunged into shadow. A drip from John's hair falls onto Sherlock's chin, runs down his neck, finds the hollow and promptly gets stuck there.

John's lips part, and his tongue goes out for some air.

"We can do it however you want," says Sherlock, matter-of-factly. "I'll have you, or you can have me. Also, it's apparently standard practise to be gentle, but you're both the doctor and the patient, so I'll defer to you on tonight's activities. Whatever you prefer."

Although temporarily lulled by the foot job, John takes umbrage at the idea that Sherlock will be having him any time soon. From under a wet fringe of hair – and John has to be absolutely sopping to even have a fringe – he glares at the long, lanky source of all his problems. His teeth return to chattering loudly in reproach.

"W-w-what I'd prefer, if you're not going to let me murder you, is to die myself so that I can stop feeling so fucking cold. No, not like that. Sherlock, what are y– Sherlock."

Sherlock delicately spits out a wet sock. "I'm continuing your therapy. The Mayo Clinic says I have to divest you of your clothing.'"

"Yes, well, when the nice people at the clinic wrote that, they didn't mean, strip your flatmate naked with your lips and teeth."

"There's nothing to prove that hypothesis." The detective gives his characteristic "this article doesn't come with illustrations" frown.

"Right. Let me be specific. I wish to die, with dignity – dignity, mind you – somewhere warm. Possibly Barbados. Have me cremated and send yourself the bill."

"Let me be specific," replies Sherlock. "You're not going to die. We are nowhere near Barbados. And the inside of my mouth is quite, quite temperate." He wraps his lips around four of John's toes and begins penetrating the spaces between them with his wet, agile tongue.

As promised, it's warm.

Oh, God, thinks John, once thinking is an option. He knows this is his own fault. Not the bit with the lake; that's all down to Sherlock. Just the bit with the toes.

Sherlock had never even heard of shrimping, but John had started meting it out to him as a correction whenever he unconsciously let his large, overactive feet bounce up and down as they read in bed at night. It was some kind of tic, and it tended to result in a lot of jostling. John thought shrimping Sherlock would teach him to be more mindful of his feet, but it only taught the blossoming pervert to love getting his toes sucked.

He has a point, thinks John, who is not the usual recipient. It feels … good. It feels suggestive. It feels flat-out arousing, and none of these things bode well for Operation Blue-Ball My Infuriating Boyfriend Because I'm Too Cold to Feel My Arse.

John blinks once to clear his head, then extracts his toes from Sherlock's mouth and sits on them to protect himself from further seduction.

That ought to teach him, John expects. It doesn't.

"Oh, hell," he says, prying Sherlock's hand off his upper thigh. "Look. Let me die with today's ration of virtue intact. I certainly don't think I need to spend my last moments on earth being touched by anyone whose actions resulted in me being half-strangled by a homicidal football player and then falling knees first into a goddamn frozen lake."

"Does f—"

"Yes, Sherlock. Fucking counts as touching."

Sherlock bows his head in theatrical submission and begins working on John's remaining boot. "You were … heroic," he says, throatily.

"And you were a berk." John corrects himself. "Are."

Sherlock gets the boot off and removes John's sock, this time with his fingers instead of his mouth. He holds the other man's foot in his hands, restoring feeling to it.

"Ow," says John.

"I love you," says Sherlock.

John stares into blue-grey eyes and sees that he means it. There's no archness, no manipulation, no self-consciousness, just the naked admission that what he feels for John is different from anything he's ever felt for anyone else. That it will always be different, and he will always feel it.

"All right," sighs John. "Get me warmed up."

Sherlock disappears for a few minutes, leaving John in charge of making his own tea. He comes back laden with pillows and festooned with towels and bed coverings. They are on his shoulders, on his head, tied around his waist.

"Be careful," says John. "My grandmother made that quilt."

"Then we'll use it as the ceiling."

"The what?"

Sherlock divests himself of his pile of linens, then shoos John off the sofa and flips it over. "I thought you'd be naked by now," he says.

"So that I could sit here starkers while you roam the flat doing God knows what? Not bloody likely. I figured you'd forget all about me and slip out the window."

Sherlock, who is wrangling the coffee table into position, gives a dismissive snort. "I'm not likely to forget you. I've been rock hard ever since you knocked that brute to the ice."

"Yeah. Because the case was over, and your libido was online again." John eases his back against the wall and takes in the proceedings. It's all you can do with Sherlock, sometimes: sit back and watch.

"Right. And because you're fit and terrifically well hung." Sherlock arranges his and John's armchairs on their sides to form a loose rectangle with the coffee table and the sofa. Then he places the floor lamp off to one side inside the rectangle.

God only knows, thinks John, nursing his mug of tippy Assam. "You can tell all that from a dump tackle?"

Sherlock nods. "That and I've seen you naked." He takes all the pillows and sofa cushions and distributes them within the rectangle of furniture, making a cushy floor covering.

"Would you like to see me naked now?" asks John.

Sherlock fixes him with a silver stare. "Yes," he breathes. He picks up the largest, fluffiest towel from his pile of fabric and drapes it over his shoulders. Then he walks over to where John is standing and pins him to the neo-Victorian wallpaper with his hips.

"Fuck," gasps John. He suddenly aches, and not with cold. The entire length of Sherlock's body is flush against him. He's trapped between his lover and the wall. John knows which one has it coming, and it's not the wall.

"I want you," Sherlock murmurs, placing a hand on John's neck. "What have you done to me?"

"Not half the things I want to do to you." John realises that Sherlock is not only referring to the post-case lust but to everything else. John is his first lover, his first flatmate, his first real friend.

Sherlock pins John's arms above his head with one hand and grinds against him. "Then let's get started," he purrs.

John swallows. Part of him is finally dry, and it's his throat. Sherlock is letting him feel his hard cock through his clothes, and it leaves him parched and panting.

"Strip me," he says.

Sherlock quirks an eyebrow. "Is that an order, captain?"

"Too right. I'm still freezing cold, and I'm dripping everywhere. I'm even getting you wet."

Sherlock groans. "You have no idea." He reaches into his own trousers, strokes himself with one finger, then uses that finger to apply a drop of precome to John's lips. Unable to stop himself, John slowly licks it off while Sherlock stares, pupils utterly blown, at his tongue.

Oh. My. God, thinks John. It's his last coherent thought for at least 180 seconds.

Three minutes of thrusting, thrashing, and begging later, Sherlock and John are both naked, and John is being rubbed everywhere by a large, fluffy, highly intrusive towel.

"Get off," protests John. "I'm dry already." Sherlock takes this as carte blanche to drop the towel, grab John's biceps as a steering mechanism, and back him up slowly into the coffee table. When John's calves make contact with the furniture, Sherlock topples him over and onto the soft mass of pillows and cushions on the floor.

Sherlock snatches a navy blue duvet off the floor and drops it on top of him. He places the mug of tea where its owner – its real owner, not the transitive one – can reach it.

"Lie there," he instructs. "I'll be with you in a moment." Then he drapes the remaining bed coverings over the furniture, using the floor lamp as a tent pole.

The use of a tent pole other than the one currently springing from John's pelvis strikes the reclining man as redundant.

In hypothermia, the body devotes all its resources to what it considers its core functions. John's core functions are apparently located between his legs. That's where the bulk of his blood flow has ended up.

"Hurry up," demands John. "Bring lube." He can hear Sherlock bustling around, securing the ceiling of the makeshift tent.

It's warm and cozy inside Fort Sherlock. More so when the Lord of the Manor crawls in, a clear bottle clenched between his teeth, and lies down beside his Man-at-Arms.

John wraps one arm around Sherlock and softly bites his cheek. "What brought this on, eh? That documentary on bowerbirds, most likely. You little vixen, you. Why didn't you tell me that Attenborough gets you hot?"

Sherlock huffs, annoyed to have been caught watching telly. "Hardly. Basic medicine, John. The Mayo Clinic says you need blankets."

John's tongue traces a slow circle around the rim of Sherlock's ear. "Fascinating. What else does it say I need?"

"Indirect heat," reports Sherlock. With John still draped around him, he props himself up just enough to take a long, hard swig of John's tea. He lets it swirl around in his mouth a good fifteen seconds, then tilts his head back so that John can admire his throat as he swallows. This done, he pushes John over on his back and disappears beneath the duvet.

John moans as a pair of tea-infused lips wrap themselves around his cock. He is experiencing the warming qualities of tippy Assam somewhere he never expected to find them.

Sherlock deliberately works John's foreskin down over his glans with his tea-warm tongue. His touch is soft and sure and maddeningly pleasurable. John feels like he's being sexed to death by debauched butterflies.

"Fucking hell," says John. He silently promises to make tea for the other inhabitant of the fort more often, if that's even possible. Sherlock swirls his tongue over the head of John's cock, checking in with all of his most sensitive nerve endings and setting his body on fire. There is a flutter of air against John's thigh as the other man breathes in deeply. Then John is enveloped down to the root in smooth, blissful heat.

Panting, he peers under the duvet. Sherlock's curly head bobs up and down as he services him. The sight of his erection repeatedly breaching his lover's pink, willing mouth is so erotic that John involuntarily lets go of the bedclothes and falls back against the pillows.

"Gorgeous," he says, thrusting into warmth and welcome. "You're so gorgeous. How am I supposed to hold out against you? The whole time in the park, it was bitter cold. Your nose should have been running like mad. Your eyelids should have been frozen shut. You should have looked like hell on a kebab, but you didn't. You never do. You're just stunning and striking and beautiful and you look like hot, long-limbed sex in an overcoat. If the strangler hadn't come by, I would have bent you over a bench and had you."

Under the covers, Sherlock leaves off sucking John's shaft and makes his way down to John's testicles. He gives the center seam an inquisitive lick, then casually takes one of his balls into his mouth. When he clamps his lips down and hums a bit of Prokofiev's Violin Concerto No. 1 in D Major, John feels certain he has never liked classical music more in his life. The vibrations are lovely, and he's knocked off guard by the accompanying rush of pleasure.

"Guh," he says, arching off the cushions. He tries to keep the one-sided conversation going, but it's no use. "So unfair. The cold weather just makes you prettier, doesn't it? Goes straight to your cheekbones and your ... unngh, Sherlock, your mouth, your fucking mouth …"

At this point, Sherlock directs his fucking mouth down behind John's balls and licks demurely at his closed hole.

After about five minutes of this, John is twisting and turning and practically sobbing. "Sherlock. Oh God. What are you – yes, like that – I can't –"

Sherlock obviously believes he can, because he begins piercing John with his tongue.

"Stop," begs John. He presses his inner thighs against the sides of his partner's head, and the man relents. He emerges from the duvet, his face shining with John's sweat.

"What do you want?" Sherlock asks. He reaches for the lube bottle, finds it cold, and pragmatically drops it into John's still-warm mug of tea.

"I want…" says John. He swallows hard. "You lunatic. I can't believe this, after everything I just said, but I want you to fuck me."

"We don't have to do it that way," offers Sherlock. "You can penetrate me. I'm warm in more places than just my mouth."

"No, really, I want you inside me. Come on. You owe me. Anything I want, remember?"

"Anything," agrees Sherlock. He rolls on top of John and begins kissing his face, his neck, his chest. John's erection presses insistently against Sherlock's slender stomach.

"I love you," says John.

Sherlock licks a lazy circle around the rim of his navel, then smiles. "Bit of a cliché to only say it when we're about to have sex."

Fondly, John swats his hair. "Bit of a non sequitur to say it when I call you a berk."

Sherlock props himself up on his elbows and gazes seriously at his flatmate. "It's never a non sequitur when I say it. I feel it. I always do. I could say it at any point in time, and it would be the most accurate declaration I could make about myself."

"You great, cuddly, squishy romantic." John traces one of Sherlock's cheekbones with his index finger.

Processing this, Sherlock rubs his head against his boyfriend's palm like a cat. "Nobody's ever called me that before."

"Doesn't make it not true. Now come up here and do me already."

Sherlock orients himself between John's thighs, then plucks the lube out of the mug of tea. "Warm now," he says, coating the fingers of his right hand.

John giggles. "Leave it to you to come up with tea as a sex aid." He lets his legs fall open to give Sherlock better access to his arse.

"Mmm." Sherlock places a hand at John's entrance, then finger-fucks him as only a violinist can. A shiver goes through John as he takes in Sherlock's rapt expression. It's as though he's never seen his fingers disappear into another man before. Three months ago, before John, he hadn't.

"Ready," says John. "Nnuh. I'm so fucking ready." He picks up the lube and distributes a healthy dollop over Sherlock. He relishes the feel of his lover's cock against his fingers – the fine, sensitive skin at the head; the bulging vein; the twitching shaft; the lush, dark fur at the base.

Sherlock takes his fingers out of John and grasps him by the calves. He gives John a questioning look.

"Yeah," says John. "Go ahead. Warm me."

Sherlock places his lover's legs over his shoulders and lines himself up. John feels a slight pressure against his hole. Then he gives a long, shuddering exhale and lets Sherlock in.

"Oh God," says John. "I can feel you. All of you. The ridge around the head, your shaft, your balls against my rim."

Sherlock gasps. "John," he says. He's fully aroused, and his voice is near subsonic.

"Do you have to say my name like that?" moans John. "It makes me want it, makes me desperate, fucking hell, Sherlock."

It's true, the way his lover says his name goes through him. Coming from that mouth, it's not a moniker; it's a mating call. Sherlock once showed him how it looked in the International Phonetic Alphabet: dʒɒn. "See?" he said. "Exotic." The way it was written is how Sherlock says it, with a strange consonant and a mellifluous vowel. That one syllable can make John pin his sweetheart to the mattress or push him up against the brick wall behind Angelo's. Once, after hours, John almost bent him over some random DI's desk at NSY. When Sherlock says it, John's name is mysterious and dangerous and dark. It sounds like sex under an orange cart in Cairo's Khan el-Khalili bazaar. At the very least, it makes John want to get taken arse-up on the back seat of a police car.

"Makes you…?" asks Sherlock. He's more than a little dazed with lust. "Then yes." He scoops up some lube that has made its way down John's thigh and applies it to John's erection, making sure to get him slick and wet.

John has it on good authority from Mrs. Turner that Sherlock's sex voice – the voice that comes out of him when one of them is inside the other; not his regular voice, which also happens to be made of sex – rattles the crockery next door. Too bad, thinks John, as Sherlock strokes him without and within.

"Fuck, yes, have me. Put it all the way in. Yeah, that's how I want it, just like that…"

"John, please," says Sherlock, as his hand makes long, rhythmic passes over the other man's sex. His pupils are so dilated it's not at all clear he can still see. He's begging, but he's too far gone to explain what it is that he wants. "Please, John. You feel so good…"

"You too, love. Feel me, feel how open I am for you."

John loves this position. There is nothing better than lying on his back with his legs unable to reach the mattress as Sherlock pistons into him. He feels vulnerable and open and thoroughly turned on. He groans as Sherlock works his foreskin back and forth over his sensitive cockhead.

"Look at you," says John. "Are you going to come? Yeah. Definitely. It's building up in you. You can't stop it."

Sherlock moans and trembles.

Something about John's posh, pristine lover makes him want to talk like a sailor. Completely other branch of the military, but still.

"Been six days since you let me touch you. I bet you thought about it, though."

Sherlock scrunches his eyes shut and nods. He slows his thrusts, trying to maintain some kind of control.

"So busy with the case," says John, breathing hard. Sherlock's hands are shaking. His motor control is starting to go. John joins his hand to Sherlock's so that the two of them can stroke him together.

"When you come," he says, "you're going to feel it everywhere – all over your body. You're so full now, you're ready to burst. You're going to fill me. Every time I look at you, I'm going to know it was you who did this to me. I'll know you licked me and opened me up and put your come inside me. I'm going to feel you for a week."

Sherlocks eyes snap open. "John," he says, his voice slightly panicked. "John, I …"

"I know. I love you. Let go."

Sherlock's mouth forms the second letter of John's name as the orgasm takes him. He keeps his eyes on John, and John knows he is doing this on purpose, letting him see him at his most vulnerable and overwhelmed. It drives him crazy to see his lover like this: all logic gone, rutting like an animal, decimated by desire, pulsing and thrusting and throbbing out his pleasure. Sherlock's wetness inside him is enough to spark John's own meltdown, and he is knocked flat by a spiraling tide of sensations that are inescapable and relentless. For a moment, he feels like he can't move his arms or legs. His body is both present and absent; both pinned to the bed and floating above it; and as he comes on Sherlock's chest, the two of them cry out, writhing and naked and claimed and loved.

Four weeks later, Sherlock falls into the Serpentine on what is, fortunately, a rather warm night for January. Nonetheless, he emerges hypothermic.

"S-s-so many things you can do to warm me up, John," he says excitedly, as Lestrade looks on in horror. "Try that c-c-cinnamon lube. Do me in the bath. Fuck me on the clothes d-d-dryer. Make a f-f-fire in the fireplace and let me have you on the rug. Spank…"

"I'll take him home immediately," says John, by way of apology, but this doesn't seem to console Lestrade, possibly because every one of the detective's plans involves spending time at home. He immediately turns redder than Sherlock and dispatches a junior constable to drive the two of them away from his crime scene and back to Baker Street.

"Crazy bugger," says John, three hours later. He has cinnamon in places where no cinnamon should be. "Next time, I'll start you on cavity lavage and leave you here."

"What's that?" Sherlock asks.

"Didn't read about that on your medical site? It's when somebody puts a tube up your…"

"Stop, stop," says Sherlock, smiling beatifically. "It sounds marvelous."

A/N: This was prompted by Atlin Merrick, whose brain-meltingly sexy "Feeding Sherlock" contains, in chapter 7, a reference to Fort Sherlock, which is made of blankets. If you haven't already read everything she's ever written, please do that now. I'll wait.

My dear, dear Atlin: Merry Christmas.

Also, the Mayo Clinic recommendations on reviving a hypothermic patient are exactly that kinky. I'll post a link on my profile page.

The image of Sherlock pinning John to the wall has a lot to do with that amazing drawing by reapersun: "Time to go to bed." It's her tumblr entry for October 11, 2011. Everything she does is gold.