Merlin's first thought is how did they end up here again?
And Arthur, he looks just as wounded and desperate as he did before and Merlin really shouldn't.
But he does.
He remembers: pale thighs straining, furiously blushing cheeks, and an unrepentant hiss to 'latch the door already, dammit Merlin!'
Gaping, he slams the door, utterly unable to process the scene before him. He would laugh at the absurdity of it all, but he’s afraid that all that will come out is a high-pitched gurgle.
And then Arthur might stop and Merlin will do anything to prevent that from happening.
He can’t help some of the wry amusement that slips into his breathy voice though. “Carry on.”
Arthur is a quivering, embarrassed mess and Merlin has caught him fucking a pie of all ridiculous things and none of this detracts at all from how unbelievably much Merlin wants in that moment.
Because he does want, has wanted, will always want Arthur, Arthur who is currently cock-deep in mashed pastry, arse flexing and displayed prominently right there in front of him, pie visible between his thighs and eyes flashing over a sun-bleached shoulder.
Licking his lips, he approaches the bed slowly. He knows Arthur is inexperienced — the sight of his huge eyes and wan face after Uther had growled at him about bastards and liaisons with servants yet again had assured him of that — but he hadn't realised how much.
He wants to gentle him through it, pet his flanks like the skittish pony he is and open him up until he writhes and moans Merlin's name. Only his name and no one else's.
Arthur is only sixteen, but he is already Merlin's king and Merlin will never bow before another. The thought of Arthur bowing underneath him, trembling, in the privacy of his own rooms sets Merlin pulsing and throbbing, the heady rush of it making his vision swim.
Merlin will take care of him and protect him in this as in everything, two halves inextricably intertwined.
And, dammit, Merlin is a teenager too and if anyone expects him to stare at the tight, virgin clench of Arthur between his arse cheeks and not unquestioningly follow his cock forward, well, they’re crazier than the dragon that’s probably laughing at them below the castle.
Because Merlin remembers the older boys, the ones who’d pinned him down and growled pretty, filthy, impossible things in his ear in the haylofts of Ealdor and then shown him exactly how much they could strip him of his senses until his body was liquid in their hands.
There are some benefits to being a country boy and Arthur has never had that, never had someone to teach him exactly how his body can bend and shake at another’s will.
The last truly conscious thought he has is that he is greedy, at least in this, and he wants it all and he’s never going to let anyone else see Arthur like this, exposed and open. Desperate.
“I can help you, if you want, you know. Make it feel even better.” His voice is a high whine, but Arthur only shivers, hips shoving forward the tiniest, involuntary bit and Merlin takes that for the acquiescence it is and pulls himself onto the bed, dropping to his knees between Arthur’s splayed legs.
He nudges Arthur’s calves and spreads his thighs wide, until the thick muscle there is straining and taught.
Someday he is going to turn Arthur on his back and push those husky, impossibly strong thighs back to his chest with a bruising grip, giving Merlin the perfect view of his cock slamming into him while Arthur can do nothing but take and take and take.
But first Merlin eagerly palms the firm, round arse in front of him, breathing hotly over every inch of skin he can reach and murmurs, “Like this.”
As Merlin licks slowly and carefully all around, Arthur unfurls below him, gasping and kneading at the sheets, the strained bow of his back pleading for something, anything, for Merlin to go in-in-in.
So Merlin does, thrusting over and over, until his jaw aches and spit runs down his chin and Arthur screams something that might be Merlin’s name or might be a curse, a promise, everything.
Arthur shudders and thrashes below him and it is the most perfect thing that has ever happened to Merlin: Arthur at his mercy and the faint, sweet smell of pie over salty skin.
Later he’ll ask, “A pie, Arthur, really?” But then he’ll lick up every sticky scrap from Arthur’s oversensitive cock in apology, until Arthur is hard and wanting, and he’ll show him exactly what a warm mouth can do.
Arthur’s libido will never be the same and Merlin will wonder whether someone can die from too much sex — Arthur bent over in the armoury, arms twisting in Merlin’s hands where they pin them behind his back, begging for Merlin to take him, to never, ever stop; or Merlin spread out in his bed, tied down in the new, strong knots Arthur had spent the entire summer learning, unable to do anything but twitch ineffectually and gasp, because oh gods, Merlin had taught him well, so well, oh fuck, Arthurarthurarthur; or late at night in the throne room where Merlin groans in Arthur's ear about how exactly he will lay the crown on Arthur's head and then spreads himself over Arthur's thighs and hangs onto the high-backed chair, Arthur only able to grip the armrests and make tiny, pained noises as he thrusts upwards.
He does end up spending hours pouring over all — and he means all — of Gaius’ books, searching just to be sure that their cocks really can’t fall off, because now that they’ve found all the perfect ways to use them together, that would be the greatest travesty in history.
Or at least that’s how it seems to Merlin at seventeen.
At oh-my-god-I’ve-been-on-this-planet-forever-why-would-anyone-expect-me-to-keep-track-of-years old, it’s a very different world to say the least.
Except that Arthur is still fucking a goddamned pie.
Of all the bloody things for them to repeat exactly it had to be this.
Merlin shuts the door behind him. He might be impossibly old, but he’s put himself back in a seventeen-year-old’s body and it still responds cock first apparently.
He shouldn't. He really shouldn't.
But it’s been over a millennium and Merlin isn’t even sure he remembers the feel of Arthur’s soft, young skin or the wrecked gasps he used to make. There will be plenty of time for callused, work-roughened hands and large, broad shoulders later.
For now, Arthur is his as he’s always been and Merlin will be damned if he isn’t the first to learn every freckle and bitten-off moan this time around.
He’s a greedy bastard like that.