As a child, Arthur preferred to play Cops and Robbers over Dungeons and Dragons. He wanted to watch action films over fantasy films. He made his mom read about knights and swordfights but slept through the wizards and spells. He was all over the Power Rangers and never got into Harry Potter.
Arthur just never understood what was so exciting about magic.
So three months into their relationship - after well over a year of knowing each other through college and flirting callously until Gwen told them to stop being coy about it and just start fucking already, after they move in together to save on gas money and bringing spare clothes and actually having to work for waking up tangled together, after Merlin gets edgy and distant and nervous around him and Arthur can't figure out for the life of him why - when Merlin finally gathers the courage to tell Arthur he has magic, Arthur's only response is a highly intelligent "Oh. Cool."
It turns into a fight, because Merlin is a ridiculous ball of insecurities and fears with ears of proportional size and Arthur loves him for every bit of him (particularly his ears) and doesn't understand why it should be a big deal. If anything, he's a little upset Merlin felt it necessary to hide it from him in the first place, but as his boyfriend blathers on about "being a freak" and begging Arthur not to sell him to the Discovery Channel, Arthur resolutely kisses him until he shuts up and tells him to order a pizza for dinner.
And after the whole debacle, Merlin's big Coming Out of the Wardrobe ('because you're already out of the closet and this is way more Narnia than Burt and Ernie') breezes past as nothing more than a hiccough. Nothing changes, except now, when Arthur is too lazy to leave the cozy warmth of Merlin snuggled against him on the couch, he noses at his neck and kicks at his feet until he floats the remote to them. When they crawl into bed after a long day of work and Arthur forgets to turn out the lights, he wraps Merlin in their satin sheets and tucks his knees behind Merlin's until he gives in and floods them in darkness. When Arthur's lost his keys or Merlin manages to knock his fifty-billionth cup off the counter or they forget to grab forks when they camp in the living room with takeout, a few eager nudges on Arthur's behalf and Merlin magicks their troubles away (because the bathwater not being hot enough when Arthur has already built a bubble fort on Merlin's head is definitely troubling).
One day, Arthur comes home from work exhausted to the bone and finds his boyfriend sprawled out across the couch, all gangly limbs and inhuman contortions because there is no reason his tiny frame should be able to take up that much of their generous couch.
"Hey you," he says cheerily, grinning that wildly untamable smile that fills the room upside-down for all he's draped over the armrest. Arthur laughs at the sheer absurdity of it and has to kiss him, hands braced on either side of Merlin's head as their lips slot together perfectly despite the odd angle. Kissing like this always makes Merlin bubble up into giggles: he calls them Spiderman kisses and they argue over which one of them is Peter Parker and Mary Jane, because Arthur wears the suit but Merlin has the superpowers and it's only ever settled when Arthur licks the breath from Merlin's mouth until he concedes with a 'fine, fine, I don't care, I'll be Mary Jane, just fuck, kiss me more, now.'
Merlin can be demanding when he's horny. It's impossibly endearing.
This time is no different as Merlin grabs onto Arthur's tie and tugs him down closer. Arthur hums into it, doing absolutely nothing to help his inverted undressing of him. It doesn't get very far at all (Merlin has enough trouble with coordination when he isn't hanging upside down), and the humming turns into laughing at the adorable pout on his Oh-So-Very Powerful Warlock's lips. Arthur has to trace the jut of his lower lip with his thumb, and then Merlin goes back to tugging on his tie.
"I've got it all figured out, Arthur," he says excitedly, blue eyes lighting up like the morning sky, and Arthur grins indulgently as he toes off his shoes.
"Everything? Call the Times, they'll want to ask questions." Merlin gives a petulant tug on his tie and Arthur laughs again, shrugging out of his suit jacket to toss it haphazardly onto the coffee table. "All right, all right. What've you figured out, then?"
"Me. I mean, us. This." He scrambles to sit up without releasing his makeshift leash, and Arthur's shoes and coat drift their way into the closet to be stored properly. Arthur quirks a brow and looks as Merlin inquisitively, whose grin only widens like he's a million dollar idea. "I'm a genie."
"You - what?"
"No, no, it all makes sense. I'm a genie, and I'll make your wish come true, but there's a price to pay."
Arthur frowns, confused. "I don't know that you earned the right degree to go into prostitution, Merlin."
"Arthur," Merlin whines, but his fervent smile stays on, and he starts running his hands down the silk of Arthur's tie. "Arthur, I'm a genie in a bottle, and you've got to rub me the right way."
"Oh my god. Are you Christina Aguilera-ing at me right now? Is that what's happening?"
"Arthur, Arthur, come on," he scoots back along the couch without releasing his grasp on the tie so Arthur has to climb over the armrest to follow, much to Merlin's glee. "Come on and let me out."
Arthur laughs and shakes his head, crawling along with Merlin's squirming until he's covering the length of his body, weight rested on his elbows on either side of Merlin's head and one knee wedged between Merlin's thighs with just the right amount of pressure. "I know the right ways to rub you, Merlin."
Merlin lets out a delirious sounding giggle and Arthur catches his lips to mold it into a moan. They're all tongues and teeth, sucking mercilessly at each others' lips and then soothing it over with playful licks and the sound of their breaths mingling between them. Arthur brings one hand to bury in Merlin's hair and tug a little, just the way Merlin likes it, before dragging feather-light scrapes down the sensitive skin of his long, beautiful neck. They've spent hours, days, learning every inch of each other with fingers and tongues and kisses and sweet nothings, and Arthur grins victoriously when brushing behind Merlin's ear earns a muffled gasp of pleasure.
"Is that so?" he teases and does it once more just to hear Merlin gasp despite himself, "Mm, how interesting. Please, tell me more."
Merlin's breath hitches again as Arthur slips his hand beneath his shirt and slides it up the length of his chest to outline the dips of his collarbone. His hips instinctively stutter against Arthur's knee, which makes him moan louder and Arthur grin. "Hate - hate you," he breathes harshly, trying to pout between ragged breaths and stolen kisses.
"Hey, you started it, Mr. Aguilera. I'm just," he pinches a nipple gently and trails his nails along the ticklish areas of Merlin's sides, "rubbing you the right way."
"A-Arthur -" Merlin cries out quietly as Arthur's fingers dip beneath the band of his briefs and trail over the tip of his cock as it fills and threatens to slip out over the top of his low-slung jeans. Arthur presses his hand flat against Merlin's erection, just to give it some pressure, and nudges his knee further forward. Merlin actually whimpers and tries to grind against him, but Arthur tuts and holds him down with his own hips, which only seems to make Merlin flush further.
"I thought you said I have to do this, hm?" He brushes their noses together and palms at Merlin's crotch, gasps and moans heating up against their barely touching lips. "This is what you needed, right?" His hand slides lower to squeeze carefully around the jeans covering Merlin's balls. He cries out and ruts uselessly against Arthur's hips, desperate for more friction, more touch, more, just more. "Do you want me to let you out?"
Arthur chuckles lowly and kisses him, still rubbing, still teasing and drawing out muffled hiccoughs and gasps against his lips, before he looks into Merlin's eyes where scarcely any blue is left to be found. "Go on, then. Take it off."
Their clothes are stripped from their bodies in a flash, the slim ring of blue left in Merlin's eyes changing to gold as he sends everything from their jeans to their socks flying across the room. Later, Arthur will find his tie spinning around on the ceiling fan, but for now - all he sees is Merlin's pale skin spread out beneath him in stark contrast to his golden tan, the heated flush of red spreading across his cheeks that likely mirrors his own, and his lips. Always Merlin's lips.
Merlin may have just vanished their clothes without lifting a finger, but it's the kiss-bruised red of his lips that enchants Arthur.
All teasing stops near immediately as Arthur kisses away the lovedrunk grin on Merlin's face and starts stroking his length, lightly at first, then giving a good squeeze. Merlin breaks the kiss to cry out in pleasure, and Arthur sinks his lips to Merlin's throat, just long enough to suck a mark into it before disappearing down his body. He tries to cry out Arthur's name, but it's lost on a moan when the head of his cock is lost to the heat of Arthur's mouth, to the feel of his tongue running circles around the crown. Arthur lets Merlin thrust into his mouth, taking him as deeply as he can and then a little bit further, swallowing around him until it hurts just a little bit in a familiar way.
But then Merlin stops him with a hand in his hair and a breathy muttering of his name. "Arthur, wait. Let me -" Arthur hums his discontent around Merlin's cock and sucks tighter, hollowing his cheeks and Merlin groans, "Arthur, you jerk."
He concedes with a laugh and lets Merlin pull him back into a kiss, follows him over until Merlin's straddling his hips, and doesn't question him when his eyes glow again as he reaches behind himself. Merlin's breath hitches and he starts rocking back against his hand, fucking himself open on his own fingers, and Arthur feels the air leave his lungs with a loud whoosh.
"Did you - ?" He slips a hand beneath him and presses a finger alongside Merlin's two, and gasps harshly at the slick wetness there. It's thicker than their lube and hotter, tingling with Merlin's magic. "Jesus."
Merlin laughs airily, "Didn't read that one in a book."
Arthur tries to laugh along but he can't for how painfully turned on he is, watching their fingers sink into him, his cock bobbing along, red and dripping. He breathes harshly and looks up to see Merlin looking right back, earnest and bright and "God, you're beautiful."
Merlin flushes a brilliant red, one Arthur only wishes could be caught on film or in paint or by the sunset, but it's only there on Merlin's cheeks, here, with him, for him. "Can I - ?"
Arthur simply nods, refusing to look away from Merlin's eyes, and gasps when a slick hand wraps around his cock. The same ethereal warmth, Merlin's warmth, and they keep their eyes on each other as they work themselves to impossibly new heights. He adds a second finger (fourth, now) and pushes in deep to seek out that particular bundle of nerves and Merlin cries, fighting not to close his eyes in the intense burst of pleasure but failing when he grinds down and hits it again.
Both hands pull free to press flat on Arthur's chest, "Please, please, Arthur, I can't -" but he cuts himself on Arthur's lips, trembling and desperate and so close to the edge. Arthur brings his free hand to cup Merlin's cheek, brush his thumb across the sharp cut of bone and kiss him tenderly. Merlin whimpers with the softness of it, the affection of something so simple in the middle of something so filthy. A fond warmth spreads low in Arthur's belly and he doesn't break the contact even as he lines himself up and slowly, slowly buries his cock inside of Merlin.
A moment passes with just their lips moving together, and then Merlin starts rolling his hips, pushing Arthur in deeper and working his own cock pressed between them. It's not enough to get them off, but it's enough - gentle kisses, soft breath, flushed together as close as possible, and it's enough.
After long enough to settle their breaths, though, Merlin sits up and Arthur laces one of their hands together, the other firm on his hip to help him by meeting him with a thrust at every rise and fall. Eyes locked with only their breath between them, Merlin mouths silent moans until they turn into cries, and Arthur moves his hand to pump Merlin's cock, drawing out more cries and thrusting in deeper to draw out louder cries. The most powerful warlock in the world, mewling in unabashed pleasure and squeezing Arthur's hand - and maybe that's something magical.
When Merlin comes across Arthur's stomach and his body clenches tight around Arthur's cock, it only takes a few more thrusts for him to follow afterwards, and they ride each other through it until the stars only shine for them. Merlin cleans them both up and drapes himself across Arthur's chest, humming contentedly while playing with their interlocked fingers.
"I'm pretty sure I promised you a wish."
"I didn't pay you, Merlin, and I'm not going to."
"Come on, there has to be something you want."
Arthur stays quiet, smiles to himself. "I already have it."
It takes Merlin a moment to respond, and when he does, he pulls free from Arthur's hand to sit up and look him in the eyes. "I think you said something really sweet just now. I need to text Morgana - she doesn't believe me when I say you have a heart."
"Do it, and I'll tell her you used Genie in a Bottle to get me into bed."
"Whatever. I've used less than that before."
"There is nothing less than that, Merlin. You've reached rock bottom, there's nowhere lower to go."
"I can think of somewhere lower to go."
"Hey now, that's still sensitive. You're going to be the death of me."
"And you're going to like it."
"No, I'm going to love it."
And when Merlin kisses him grinning, maybe, just maybe - it's enough to make Arthur believe in magic.