They discover it by accident when, the next time Merlin calls for Kilgharrah, it is Arthur who walks into the clearing first. The prince is half asleep, dressed in his night shift with his hair rumpled and soft around his face, and he and Merlin stare at one another for a long moment before Arthur takes a step forward, pointing a finger at Merlin in warning.
“Not a word,” he says, eyes narrowing. “To anyone.”
“No, sire,” Merlin agrees, although he’s having trouble holding back a smile. Arthur notices—of course he does—and scowls like he knows what’s going through Merlin’s mind.
“I mean it, Merlin.”
“Who would I tell?” Merlin asks pragmatically. “No one but Gaius knows that I’m a Dragonlord. And I won’t tell him if you don’t want me to.”
When the prince turns back towards the castle, however, padding bare-footed and careful over the uneven ground, Merlin can’t resist hissing after him, “Stumble.”
Arthur’s footsteps falter for a moment before picking up again.
“Nice try, Merlin,” he calls over his shoulder. “But I’m not actually a dragon.”
Whatever it was that had summoned Arthur to him, it wasn’t the same as a true compulsion; perhaps because Arthur is human and not dragon-kin, Merlin’s magic works on him in the manner of a strong suggestion, which the prince can usually shake off so long as he’s paying attention. Arthur describes it as being a kind of friendly nudge, as though Merlin had slipped his arms around his waist and whispered something filthy in his ear—not his exact words, maybe, but what Merlin deduces from the way Arthur’s cheeks go pink when he talks about it, the pupils of his eyes dilating an almost imperceptible degree.
“I wonder if your family has dragon blood,” Merlin muses, thumbing through one of Geoffrey’s texts on the royal family tree. As dry and dusty as it is, Merlin doesn’t expect such a secret to be hidden within its pages, but there are tantalising hints of an answer here and there, not the least of which lies in the name. “That might explain it.”
“It might, if humans ever mated with dragons,” Arthur says, rolling his eyes. “But I think anyone who tried it would be burned to a crisp. Not to mention the fact that they’re a different species.”
Merlin lets the matter slide after that, but it’s a legitimate question. It’s not as if there aren’t spells for shapeshifting, after all, and with the proper motivation, a sufficiently gifted sorcerer could do just about anything.
He wonders if that’s where Dragonlords came from.
The subject which truly exercises his imagination does not arise for several days, although Merlin realises later that Arthur must have been thinking about it for some time before he brought it up. Arthur has a series of complicated rules when it comes to sex, the ins and outs of which Merlin is still trying to understand, but the most important one seems to be that if he doesn’t acknowledge it—if they just don’t talk to one another about it—then outside of the moments they spend tangled up with each other’s arms, cocks, fingers and mouths, he gets to pretend that nothing is different. In the morning, when Merlin slips from the prince’s bed to dress and stoke up the fire, Arthur remains determinedly insensate, refusing to wake up or even stir until Merlin returns with his breakfast and begins the morning chores, neatly installed in his role as manservant once again.
In all of Merlin’s speculations, therefore, he has always assumed that he would have to be the one to bring up the incident in the forest, always supposing Arthur will agree to talk about it at all; which is why it comes as such a shock when, as Merlin is sliding into bed beside him one evening, Arthur puts down the book he has been reading and turns to face him.
“About the other night,” he says.
“I didn’t mean to,” Merlin says at once. After so many years as Arthur’s manservant, the response is almost a reflex, and he knows without having to look that Arthur is grinning. “Shut up. You know I’m not going to use it.”
“I know.” Arthur is silent for a long moment, so long that Merlin thinks maybe he’s fallen asleep. Then he says quietly, “But…what if you did?”
Merlin’s head snaps up. What he can see of Arthur’s expression appears faintly embarrassed, but he meets Merlin’s gaze with determination, a familiar stubborn set to his jaw.
“You…want me to—what, to order—?”
“It’s just an idea,” Arthur says hastily. “You don’t have to. I just thought you might…want to.”
“I’m not sure I know how,” Merlin confesses, although he has to admit that he’s been thinking about it. Rather a lot, as it happens. Besides, anything that makes Arthur curious enough to make the first move must be worth investigating; never mind that it’s hardly an imposition and Merlin has said as much on multiple occasions, it’s still a rule that Arthur hardly ever breaks. Until now. “But I can give it a try, if you like.”
From Arthur’s sideways glance, he’s not altogether keen on being an experiment, but he settles against the pillows without a word, so Merlin figures he might as well give it a try.
“Kiss me,” he says bluntly, deciding to start with something simple and to the point. It’s strange, using Dragontongue without a dragon present—without even the intention of summoning a dragon—and although he waits for a moment to give the command time to take effect, nothing happens. Arthur remains firmly ensconced on his own side of the bed.
“Kiss me,” Merlin insists, more firmly this time. “Arthur, come here and kiss me.”
No response. Smirking at him blithely from across the pillows, Arthur says, “You know, Merlin, if it’s too much trouble—”
“Shut up,” Merlin growls, unthinking, and it’s only when Arthur opens his mouth to speak—then snaps it shut again, looking surprised—that he realises what he’s done. “Oh, god,” he says, scrambling to sit up straight. “I’m sorry—I didn’t actually mean—”
Arthur cuts him off, however, by the simple expedient of kissing him on the mouth, and Merlin lets out a soft ‘oh’ as Arthur pulls him into his lap and slides a hand up his shirt, demonstrably not displeased by this turn of events.
“So that’s how it is, is it?” Merlin murmurs, straddling Arthur’s hips. He can feel Arthur’s cock beneath the blankets and rocks against him, biting down on Arthur’s lower lip as the prince opens his mouth in a gasp. “You’re going to make this difficult.”
Arthur just smiles guilelessly, which Merlin takes as an affirmative, and also as permission to turn the kiss filthy, licking his way into Arthur’s mouth and grinding down with his hips in a way that makes Arthur let out a soundless moan. The prince rises to meet him, hands roaming over the flat planes of Merlin’s chest, his head tipped back and his eyes slitted, cat-like with pleasure. “God, Arthur,” Merlin groans, lips sliding from Arthur’s mouth to his jaw; his neck. “You have no idea how much I want to fuck you right now.”
Arthur lets out a huff of what might be laughter, fingers tugging at the hem of Merlin’s tunic before dipping below his belt. “Yes, I know,” Merlin says, in response to the unspoken teasing. “I have too many clothes on for that.” He pulls off the shirt first, nearly braining Arthur with an elbow as he does it, and is unceremoniously shoved off the bed. “Ouch! Fine, hang on—”
The breeches follow, then his smalls, and then he’s naked and scrambling for the vial of oil Arthur keeps in his bedside drawer, nearly knocking over some of the other bottles in his haste. Arthur waits almost patiently, his hands fisted in the material of his coverlet the only sign of his growing agitation—at least, until you look into his eyes.
“You can—you know. Get started,” Merlin says awkwardly, still fumbling around checking the labels. “I’ll only be a second…”
But the prince just looks at him, making no move to hurry things along, and Merlin trails off, studying Arthur’s face. He looks torn between arousal and humiliation, his gaze sliding away from Merlin’s eyes where they try to meet his. “Unless…You want me to order you to do it?”
An almost indiscernible nod. Arthur’s cheeks are flushed red, and Merlin’s pretty sure his are, too, but his cock is already hard and aching and it’s not as if he’s going to turn down a chance to boss Arthur around. Cautiously, his eyes on the prince in case he changes his mind, Merlin reaches again for the voice he usually uses on Kilgharrah and says simply, “Touch yourself.”
Nothing happens. Arthur is still watching him, one eyebrow raised and a hint of defiance in his eyes, and all right, if that’s the way he wants to play it—
“Touch yourself, Arthur,” Merlin repeats, more forcefully now, sheathing the words in power as though coating a bitter pill in honey, and he catches the flare of gold in Arthur’s eyes before his head falls back, his breath escaping in a surprised rush as he reaches down—and does it.
He’s hard beneath his shift, that much is obvious. Merlin can just see the flushed head of his cock as he works it under the covers, his thumb sliding over the slit in a way that makes Merlin bite his lip to contain his moan. Arthur’s chest is heaving, his eyes screwed shut like it’s a struggle to keep himself silent, but he doesn’t make a sound.
“Arthur,” Merlin whispers. Arthur’s breath hitches, hips stuttering upwards, and Merlin lets out the sound for him, a strangled, half-swallowed groan. Grabbing a vial at random, he crawls up the bed towards the prince, his prick heavy and straining between his thighs, and pulls the covers back to expose Arthur’s frantically moving fist, the soft weight of his balls drawn up like he’s already on the edge. Arthur whimpers a little, tendons in his neck straining, and somehow Merlin knows that he’s holding off, unable to come without instruction.
The thought makes him dizzy. “God, you’re so,” he breathes, not really knowing what he’s intending to say. “You’re so—Fuck, Arthur, can you turn over for me?”