It’s not like Merlin ever intended to watch Arthur bathe.
As the prince’s manservant, he’s expected to be on hand for whatever Arthur wants, whenever Arthur wants it, and Arthur becomes particularly imperious when submerged in the tub.
“Fetch me that bar of soap, Merlin,” he will command, pointing. “No, not that one. That one. And bring me another washcloth while you’re at it. Don’t just stand there gawping at me, you idiot—the water’s getting cold!”
By rights, Merlin is supposed to wait discreetly behind the changing screen when he isn’t needed, like a good little servant pretending to be just another part of the furniture. And he tries. He really does. The problem is that the changing screen is one of those silly, decorative ones that doesn’t actually, well, screen very much—and the other problem is that Merlin can hear.
Splashing. Slightly ragged breaths. A low moan, quickly bitten off as though by royal teeth.
He should probably turn his back, but he can’t move. Through the latticework that stands between them, he can see Arthur with his head tipped back, his knees splayed open, and although Merlin can’t actually see his cock, after weeks of enforced proximity he can imagine it: thick and red, the slick head protruding from Arthur’s fist as he works his way slowly along its length.
Has Arthur forgotten Merlin is there? It seems unlikely, considering that he’d been ordering him about only a few minutes before. Which means that either he doesn’t particularly care that Merlin is listening, or…
Or maybe he wants Merlin to hear.
The thought makes Merlin flush all over. He’d grown up in a small country town where half of the townsfolk bathed nude in the summer, so he’s never been exactly shy about the workings of his body, but he’s not sure whether Arthur’s just a shameless exhibitionist or if he’s trying to make a point. Either way, though, if Arthur thinks he’s going to chase Merlin away by waving his dick around like it’s some kind of imposition, he’s about to be terribly disappointed.
The best and worst thing about Arthur is that, despite being an entitled ass in most respects, he is also unfairly gorgeous. It’s not exactly the first time Merlin has found himself getting hot under the collar because of the prince, or daydreaming about what it would feel like to have Arthur’s hand on his cock instead of his own. The only difference is that now Arthur is tormenting him on purpose, and what kind of a manservant would he be if he backed down from a challenge like that?
He has a hand inside his breeches before he can think better of it, unable to help a small sound of relief as his fingers close around his hardening prick. Arthur lets out another low moan, and Merlin uses his free hand to rub up against his hole, envisioning the prince pressing into him from behind while his hand works Merlin’s cock from the front.
“You like that, don’t you?” fantasy Arthur whispers, and Merlin imagines his breath, tantalisingly hot against his skin. “You want me to fuck you like this, right here, just bend you over my table and have you however I please. I’ve seen you watching me, Merlin—I’ve seen the way your hands shake when you undress me. I bet I could make you beg before you come.”
Breathing faster, Merlin speeds up his strokes to match the sounds he can hear from the tub, smearing pre-cum over his palm to make it easier. He imagines the way Arthur would tease him, pushing in with just the tip before retreating again, thumbing Merlin’s slit like he’s unaware of the way his touch makes Merlin’s body thrum like a vibrating string. Unable to help himself, Merlin shifts his weight, bearing down on his fingers as he thinks of Arthur thrusting into him, of the prince crowding him against the wall still dripping from his bath. The image of Arthur covering him, fucking warm and wet into his half-clothed body, hits him like a sucker punch and he groans, spending in a helpless rush over his fingers.
The splashing sounds stop. There is an agonising beat of silence, during which both of them seem to be holding their breath, and then—heart racing, cheeks burning—Merlin forces himself to raise his head.
The prince is staring at him through the ornate scrollwork, his eyes startlingly blue in the candlelight. Merlin doesn’t move, doesn’t even breathe, waiting to hear his punishment. Beheading, perhaps? The stocks? Or something worse, something devised by Arthur especially to torture him…But then the prince slides his hand back into the water, his eyes never leaving Merlin’s face, and slowly, slowly the rhythm begins again, the movement of Arthur’s body inside the tub unmistakably sexual. A droplet of water trickles down his neck, ending in a shallow pool at the hollow of his throat, and Merlin is fairly sure he whimpers when Arthur licks his lips and tilts back his head, a satisfied smirk curling the corners of his mouth.
This can’t be happening; it has to be some kind of trap, but Merlin is so thoroughly wrecked right now that he couldn’t escape even if he wanted to. He watches Arthur work himself lazily to a climax, his cock twitching in his smalls as though trying valiantly to get hard again, and when Arthur’s done—mouth slack, body lax, deliciously spent—he extends a languid arm and gestures for Merlin to come closer.
“Towel,” he says, crooking his fingers. “Hurry up.”
Merlin staggers forward. He drops the towel beside the bath, and is contemplating making a break for the door when Arthur reaches out and touches him, drawing a finger along his wrist in a way that makes Merlin stumble to his knees.
“Next time,” Arthur says slowly, looking down at him through hooded lids. “I might need your help with that, too.”