A/N: I originally posted an incomplete version of this. It was a reaction to FFn pulling NC17 stories a couple of weeks ago.

Today, I woke up and thought, um. Stuff that. So there you go. The complete, filthy version now.

I wrote this for marguerite_26's "First Times" Prompt Fest, in answer to this prompt from otta_ff: The first time Arthur catches Merlin wearing his crown and falls to his knees for his "king". - I found it pretty much irresistible.

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And where the hell is Merlin, anyway?

Not in the kitchens. Not in his little alcove room behind Gaius' quarters and not in the stables.

He's always underfoot, ever annoying, usually lacking in appropriate respect for his betters, but now—when his King actually needs him—now he's nowhere to be found.

Arthur huffs in annoyance, hating the mud caked on his boots. It muffles them on the cobbled stone in a most unsatisfying manner, when he wants to hammer down the halls like a fearsome god of war. He looks down at himself, nose wrinkled in disgust, vaguely wishing he was less King and more Tyrant so he could actually chop someone's head off for this indignity.

Brown globs of mud foul his favourite tunic, already drying and cracking off in chunks. The holes of his belt are clogged up and there are spatters on his cheek, the skin underneath turning dry and taut with it.

People are actually folding themselves in half and sweeping out of his way, and mud or no mud, that's just the way it should be, seeing as he's King. This makes him think of Merlin not doing that, ever, and the storm above Arthur's head crackles with impending thunder.

It has been the day from hell. Anything that could have gone wrong, has done so, and it just keeps getting worse. The whole day has been a comedy of errors which are annoying enough on their own, but when heaped into one pile, they've turned Arthur's day—and his mood—into a stinking mound of shit.

"And where the hell is Merlin?" he shouts, just to let off some steam. Unsurprisingly, he gets no answer from the prostrate servants who line the halls like they've been brushed aside by a malicious giant.

Clunking his way down the corridor and frustrated beyond reason, Arthur turns to his own quarters. If his useless manservant can't be found, he'll just have to change into clean clothes by himself.

Stomping to his rooms, he slaps the door with the heel of his palm and it flies open, banging hard on the wall and recoiling back so fast it almost hits him in the face as he stalks inside. It's such a near miss, his hair is swept from his temple by the passing breeze.

There is a brief moment where he considers splitting the insubordinate door up for firewood, feeling vaguely regretful that civic duties didn't warrant belting on his sword today. The door, obviously knowing it's safe from actual bodily harm, slams closed obnoxiously loudly behind him, the echo of it reverberating through the entire room.

Inside Arthur's quarters, Merlin startles so violently, Arthur's full ceremonial gold crown topples off his head and clangs on the floor loud as a bell, then rolls to land almost at Arthur's feet.

Merlin looks at it until it comes to a complete and silent stop, an arm's length away from the tip of Arthur's very muddy boot. "Oh."

Arthur's nostrils flare widely. His jaw is clamped so tight, the muscle in his cheek pings with tension. Merlin hasn't moved, not even to lower his arms, which are paused in the act of failing to catch the falling crown.

"Oh," Arthur grinds out, his voice full of menace. "Oh? Is that all you have to say?"

"Oh, bugger?" Merlin offers.

Arthur thinks he can feel his blood literally boiling. It's the only thing that would account for how much heat he's exuding right now. It isn't often that he's stunned into silence, but the combination of everything happening at this particular moment in time has him completely and utterly lost for words. He settles for the first incredulous ones that (eventually) pop into his head.

"You were wearing my crown." It's not a question.

"A little bit, yeah."

Arthur's mouth falls open without his permission and he quickly snaps it shut, clicking his teeth together.

"You are the. Most. Infuriating bastard—"

Merlin is indignant. "Hey! No need to cast aspersions on my—"

"MERLIN." Arthur cuts through in the firmest, most thunderous voice he can muster, teetering on the absolute edge of control. Miraculously, Merlin stops talking, perhaps realizing that to continue would be to invite a very painful death by Arthur's stabbing eyeballs, and that's just until Arthur reaches his sword. The silence feels like the entire castle is holding its breath.

"Pick. It. Up."

Arthur hadn't noticed this in his earlier shock at finding Merlin making light with his crown, but he certainly notices it now: Merlin's lip is almost, kind of, nearly, maybe about to curl in what could perhaps be loosely termed as the very beginnings of what might be called a smirk.

Merlin does not look afraid. Merlin never looks afraid, at least not of Arthur. It makes him want to screech and stomp his foot like a five-year-old. It's only a lifetime of a warrior's conditioning and of enduring Uther's ironclad version of fatherhood that stop Arthur from giving in to the urge. He has never needed his training more than right now.

Merlin steps forward, bends to pick up the crown, and Arthur bites the inside of his mouth to stop his foot from succumbing to the overwhelming temptation. He is literally trembling with fury, and though he'd never attack a defenceless person, he'd make an exception right now for his disturbingly fearless idiot manservant.

All the pent-up frustration of being King, and all the responsibility of every decision he has made in the weeks since his father's death have spearheaded this moment. The weight of it all is stabbing him in the guts like a white-hot, rage-filled poker, demanding some kind of release.

Merlin stands and straightens his shoulders, infuriatingly calm in the face of Arthur's rage. He meets Arthur's eyes with no discernible cringing of any kind and holds the crown in a loosely curled hand like it's a wooden plaything, and not priceless regalia representing Arthur's reign over all of Camelot.

"Put it on."

Merlin's eyes widen.

Ah, there. Finally, Arthur thinks, breathing deeply through his nose in triumph. Finally I have your attention, you pasty, skinny little—

"Wh—"

"You heard. Put. It. On."

Hesitating for only a moment, Merlin lifts his hand and places the gleaming crown of Camelot on his scruffy, irreverent peasant's head. He smiles, white teeth even and perfect and—

Arthur blinks.

He has absolutely no idea why he said that, and then the... and oh.

Oh.

Oh my God.

This was a very bad idea.

Just seconds ago, Merlin was an impudent, skinny servant with ludicrous ears, about to bear the brunt of Arthur's foul mood in punishment for his massive presumption.

Now, he's—

Arthur swallows dryly. Merlin's calm eyes are huge. And very dark blue. And framed like a girl's, in lashes black as soot. How has he never noticed this before?

He's taller than Arthur, and is that even right? Surely it's just the added height of the crown giving the illusion—

Arthur's thoughts crawl over each other like mice in a labyrinth, none of them finding the way out of his brain in entirety. Nothing makes sense.

In the absence of conscious thought, Arthur blinks. Twice.

Merlin's mouth is very pink and he's standing straight, tall and completely unafraid, and Arthur's knees are weak.

He has no idea what's happening.

"You look like an idiot." His voice is weak, too. He should have kept his mouth shut. Merlin will see straight through—

"Do I." Merlin says quietly, clever eyes glinting in the twilight, somehow knowing. Assessing.

"Take it off." It's a choked whisper. Arthur is horrified that his bottomless well of kingly rage appears to have turned into a vagina while he wasn't looking. At his sides, his hands clench into tight fists.

Merlin allows the pause between them to grow for long moments, before answering. "No. I don't think I will."

His words are measured. Sure. At the corner of his mouth, a smile waits to be born. He's so tall. He wears the crown so well, like he knows just what to do with it.

Arthur does the only thing he can think of.

He slowly lowers himself to his knees.

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At first, Merlin thinks, oh, crap.

Arthur barges into his quarters like a rampaging bull, his nostrils flaring with every breath, and Merlin wouldn't have been at all surprised if steam started to billow out of his nose in hot gusts.

And yes, there's the crown-shaped elephant in the room rolling across the floor, but immediately it's clear there is more to it.

Arthur appears to have been the unwilling recipient of a mud dunk, and his eyes are hard with a new kind of tightness which Merlin's been seeing more of lately. It's untouchable, sitting like a mask over Arthur's face, making him look like a stranger. Making him look like the King.

Merlin doesn't have to be a genius to work out Arthur's had a horrible day, and that any good humour he might have woken with was lost somewhere between meetings with the brain-numbing exchequer, the tedium of Camelot's mediation council, and the indignity of being slathered with road sludge.

Merlin figures he can probably distract him and talk his way around the liberty he took with Arthur's crown—it was just simple curiosity, he wanted to know if it was as heavy to wear as it looks—until Arthur comes close enough for Merlin to sense the underlying desperation beneath his anger.

At Arthur's command, he places the crown on his own head, and is stunned by the myriad of emotions wrestling each other across Arthur's face, like he's not sure which is supposed to win.

Merlin sees Arthur's silent, desperate vulnerability. He hears Arthur's crumpled plea, but his eyes are open and as blue as the sky, and so very clear. Clear enough for Merlin to see that they defy the words he speaks.

Instinctively, he obeys Arthur's eyes and defies his words, too.

Arthur kneels, and the world stops spinning. Caught in the void, Merlin does the only thing he can think of.

He allows Arthur to lead him.

He reads Arthur's cue just as he always does, and though his gut is roiling with anxiety, his hand is steady. He lifts it and gently cups Arthur's face.

Arthur's lips part with a rough exhalation, and Merlin's stomach drops through the floor. His hand looks big fitted to Arthur's cheek, all rough calluses and bony fingers, but Arthur looks beatific at the touch. His blue eyes are heavy lidded, almost rolling back when Merlin's thumb slowly caresses the sun-kissed softness over his cheekbone. They've lost the edge of their fury, his brows knitted together in furrows like he's concentrating.

Merlin hasn't felt the crown until this moment, but the weight of it is suddenly very tangible. Very real. Arthur's handsome face is turned up toward him, the plea visible in every line and every curve, and Merlin will do anything, anything at all to give Arthur what he needs.

Arthur leans very slightly into the palm of his hand, and it's this gentle encouragement that sends a thrilled shock through Merlin's arm, dispersing it through his body in a wave of heat. He feels it in the tips of his fingers and toes, and the abrupt clench in his groin is so intense, he stifles a gasp.

Testing for a boundary, Merlin scratches the tips of his fingers through the thick flax at Arthur's nape. He watches in amazement as Arthur shivers beneath his hand, on the very edge of shattering out of his skin. He's like a wild thing mesmerised, desperate to take the feed from Merlin's palm, only to bound away to safety in one screaming leap.

Trust me, Merlin conveys through the gentle sweeps of his thumb and fingers. You know you can trust me.

Arthur watches him with wide eyes, and Merlin knows he needs to be very careful. He exerts the gentlest pressure, fingertips gathering Arthur forward, and grits his teeth against a groan when—

Arthur slumps forward, nuzzling into his lap.

God, he wants this.

Merlin can feel Arthur's hot breath against the crease of his thigh, Arthur's cheek resting where there can be no mistaking his intent. Merlin waits, his breath like a coarse lump in his throat and his whole body sprung tight, praying for a little self-control when faced with all this beauty. All this possibility.

Merlin takes a deep breath and dares to want it.

With a sure and steady hand, he pulls Arthur's face forward into his crotch, rubbing his suddenly risen erection against the hard ridge of Arthur's cheekbone.

Arthur's groan is so wanton, Merlin's skin breaks out in a wave of goose bumps.

He holds the nape of Arthur's neck in his large, coarse hand, and rubs himself firmly over his cheek and jaw. Spatters of mud crumble from his skin, dusting over Merlin's clothes.

Merlin knows his jaw is slack, knows he must look wrecked. He can feel the heavy-lidded need expressed in his own eyes. Glowing strips of the dying sun fall across table, floor and bed, resting like fire brands over Merlin's hand and Arthur's face, turning bright blue eyes to bronze.

He feels the weight of the crown sitting tightly over his temple, and sees it reflected in Arthur's wide eyes, the gold as bright as the sun in the evening-darkened room.

And Arthur—the one whose needs are outweighed by the many, who clearly needs this release so much but doesn't know how to take it for himself—offers himself up instead. He pleads wordlessly for Merlin to take the master's yoke from his neck, to take him, giving himself up in a desperate moment of fathomless need.

It's all Merlin can do to obey.

Holding Arthur's neck with one hand, he burrows under his shirt and unfastens the placket of his trousers with the other, quickly untying the laces at his belly.

Arthur's breath quickens, bright eyes following the movement of Merlin's dextrous fingers, his parted mouth flushed red. Merlin expels a hitching breath, the ball of heat low in his gut flaring like a shooting star. By all the Gods, he thinks, his eyes full of Arthur's blue, gold and pink, spattered with mud and perfectly imperfect, you are so fucking beautiful.

The tarnished bronze of the sun's last rays steals through his window and paints Arthur a halo, a shimmering aura of hair glowing like embers that Merlin just has to touch. With his trousers undone, he weaves his fingers through Arthur's hair and brings him close.

He holds on through the first tentative nuzzles, Arthur's breath thick and moist. Merlin's eyes drift closed in bliss. He grits his teeth at Arthur's hot open mouth breathing on him through the thin fabric of his shirt. Arthur maps the contours of his cock with soft, lingering kisses, rubbing over it like a cat, a day's worth of stubble catching on the coarse weave.

Just as Merlin thinks he can't stand the slow torture of it, he senses Arthur looking up, and opens his eyes.

There is trust there. And still, the plea.

Merlin smiles.

Loosening one hand from Arthur's tangled hair, he lifts aside the hem of his shirt and exposes his cock, pink, hard and slender. He takes it in his own familiar grip, and pulling Arthur closer, he touches it to Arthur's lush red mouth. In the silent room, they both gasp at the contact.

Merlin draws the shape of Arthur's lovely mouth with the tip of his erection, skin to skin, touching as lightly as a feather, his swollen cockhead to Arthur's chapped lips. He snags it a little where they're dry, and loves watching Arthur's lips pulled taut by the drag of his cock. Arthur sighs, arms clenched at his sides, perfectly fluid in the grasp Merlin has on the back of his neck.

"Open your mouth," Merlin says quietly, and Arthur does, parting his lips as blood rushes to his face, unfurling bright and hot under his skin.

"Lick me," he continues in a quiet murmur, and Arthur's moist, pink tongue dances lithely over his now-glistening glans. Merlin watches it all with greedy eyes, afraid to blink and miss a single moment.

Arthur's whole body trembles under Merlin's hand, and his tongue works itself needfully—wet and serpentine—into the fold of his foreskin, laving the thick vein, slicking up the rigid shaft of him. He watches it tease the skin of his bollocks, dark hair glistening and wet in its wake, balls tightening at the sweet torture of Arthur's hot tongue flattening and curling.

Merlin can't breathe—it's like nothing else. His own hand, practiced, oiled and warm, is nothing like the hot twisting lust awoken inside him at the sight and sensation of Arthur on his knees, loving his cock. It's galvanizing.

"Arthur," he whispers brokenly, wanting only this, and at the same time, wanting so much more. At his feet, Arthur doesn't stop, but his eyes meet Merlin's over the rapidly purpling cockhead even as he curls his tongue around it, licking, licking, licking. "Touch me," he says, thrilling at how quickly Arthur takes him in a firm, damp grip, sun-weathered hand gold over Merlin's pale, pink cock.

Holy Gods, give me strength, Merlin prays, all the muscles in his body spasming involuntarily, his magic hiccupping inside him, desperate to get out.

"Suck me," he commands with as much gentleness as he can infuse into his broken voice, belying his desperate need to see those lips close over him.

Arthur holds him steady and descends on his cock with such absolute relish that Merlin gasps as velvet heat envelops him, suckling at him with perfectly delicious abandon. Arthur groans, the sensation like an earthquake in Merlin's soul, breaking his heart with its want.

Biting his lip to stop spilling out words he will regret, to stop the onslaught of love and pain and longing, Merlin buries his fingers into the hair at Arthur's nape and swallows down the pressing need to spill his guts, remembering he does this for Arthur—it's his need they're fulfilling. Hisdesperation they quell, not Merlin's.

Merlin pulls Arthur back a little to set the pace, holding him steady by a light grip on Arthur's neck and slowly pushing himself into the heat of his mouth. The need to fuck is so strong and overwhelming, boiling away in his blood, that he trembles with it, hardly able to stop himself.

Arthur's beautiful mouth sucks him in wetly, the tongue within working itself over and under and all around it in a hot and filthy embrace. Merlin watches, mesmerised, thrusting slowly in and out.

He lets Arthur have as much of his cock as he can take, until he almost gags, his eyes glinting and moist in the low light. Merlin pulls out thinking he'd gone too far, but Arthur blinks his eyes clear and follows, chasing Merlin's cock until it's hot in his mouth again and wet with spit, andfucking hell if it's not the most arousing thing that Merlin has ever, ever seen.

He groans and allows his head to fall back, resting on the knot of his spine while he tries to keep his sanity. He clenches his eyes shut, trapping telltale gold under his eyelids.

When he looks again, Arthur watches him intently from below, the sun now gone and dusk settling over his eyes in loving swathes, darkening them into the blue-black of the evening sky. The glaring reflection is gone now, no more the crown in Arthur's eyes, now just the black shadow of Merlin himself, like a thing made of night.

Those are Arthur's eyes.

King Arthur is kneeling for him. Letting Merlin fill his mouth with cock.

Oh Gods.

Merlin's mouth lolls open and he must look like the most ridiculous idiot, but it's not possible to care any less about it because he's about to shoot a record-breaking load of come into Arthur's hot, filthy mouth, which is on a mission to suck every vestige of sense out of him, directly through the eye of his dick.

Realizing that this must soon end, Merlin grapples with his tattered self-control and with wrestling his magic into submission, though it wants to shatter his fingertips into molten glass geysers, implode his lungs with the power of the words trapped inside.

He checks Arthur's face for more cues, for the need that begs fulfilling. Arthur looks up at him with bright eyes and a full mouth, and slowly relaxes his grip on Merlin's cock, letting his hand fall away.

Merlin thinks he understands.

With one hand gripping Arthur's neck and the other twined into blond hair, he feels Arthur slacken and give within the span of his hands.

He holds Arthur like he's a precious thing, a holy thing, and fucks his mouth with a gut-wrenching moan as the irreversible tide gathers low in his belly.

He tries to pull away but Arthur won't have it, won't release the suck. He digs his fingers into Merlin's hips, and coaxes out the tangled ball of light erupting inside him with brutal pressure and a coiling tongue, and Merlin can't stop it, can't stop anything.

It explodes him from within into pulsing ribbons of filthy, wet pleasure, enveloping him in golden warmth, binding him to Arthur, to the earth, to the night sky. He shouts his release into Arthur's silent rooms even as he empties between his lips, changed inside by this new reality. Held up by the strength of Arthur's arms, he rides it to the end, rutting shallowly into Arthur's unrelenting mouth until he's too sensitive, sucked raw, pulling out of the merciless heat and into the cool balm of evening.

He drops down to the floor, hard and painful under his knees, until he's eye to eye with Arthur, who's flushed and dishevelled, all swollen lips and sweaty clumps of hair, obscene and beautiful, glassy eyed and panting.

Merlin knocks the crown from his head and it rolls away in a dull metal skid across the floor, already forgotten. He gathers Arthur's face between shaking hands and eases kiss after kiss into his mouth, tasting himself, licking Arthur clean.

Arthur's desperately scrabbling, groping hands are hurting him and he loves it, loves the feeling of fingers digging into his back, bruising his shoulders, marking his hips with fingerprint brands.

Arthur kisses like he's starving, like he wants to crawl inside Merlin's mouth, leech under his skin through will alone. It's harsh and hard and like being made to kneel at the point of a blade, knowing your life is forfeit. There is no trace of the mask now, only Arthur's essence at its most distilled. Merlin loves the strength of it, the taste of it so much, he licks it from Arthur's skin, his throat, his clavicles, nipping at salty flesh and burnishing it with his fingers.

Hiding the gold of his eyes in the crook of Arthur's neck, he incants for a rug, and one appears beneath them just as he pushes Arthur to his back. Wasting no time, he wrenches and pulls at clothing until Arthur's cock is exposed and pulsing in his hand, heavy and thicker than his own.

There's no time to appreciate the gravity of the moment, no time for anything except to touch and taste and hold as much as he can. Merlin doesn't know what to do first, so he does everything, working the weight of his body between Arthur's thighs, his mouth already in the hollow between thigh and sac, eager fingers scratching furrows through coarse hair at the base of Arthur's cock.

He looks up to see Arthur's throat working, lips curled around a profanity, and oh God, please, he thinks, please. Please don't let this be the only chance I get to love you.

Arthur's close, so close already if the death grip on Merlin's hair is any indication, and he licks his way up to the head of Arthur's cock, noisy, filthy, closing his mouth around as much as he can, fisting the rest in a tight, sleek grip.

Fuck, fuck, fuck, Arthur chants, and Merlin follows the rhythm with his mouth, moving in time to the blood beating in Arthur's veins. He rides the tide with Arthur in his hand, throwing his whole body into the motion until he feels Arthur tightening, taut and rigid beneath him, so full in his mouth, so hot. When he comes, it's bitter and numbing all the way down Merlin's throat, tasting like bewilderment and victory and complete surrender.

Finally, he collapses against Arthur's thigh, panting and boneless, chest heaving with strings and clusters and galaxies of all the words he can't say.

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This can't happen again." Arthur's voice is hoarse, breath visible in the rapidly cooling night air.

"Of course not," Merlin agrees, comfortably warm under Arthur's carmine cloak, which he pulled down from a nearby chair to cover them as they lie on the floor.

He burrows closer into the solidity of Arthur's side, brushing his lips over his jaw. "That would be bad."

"Bad," Arthur repeats weakly as Merlin rasps the tip of his tongue over the stubble.

"Merlin," he says, drawing it out. A warning.

"Hm," Merlin says thoughtfully, looking him over. He inclines his mouth down to Arthur's nipple, and allows himself a small grin at the telltale stutter in Arthur's breath.

"Never again, Arthur," he says, smiling when Arthur's thighs fall open with a sigh, under the gentlest nudge of his knee.

~Fin~

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A/N: Thanks for reading!