There are many things that Arthur loves about Merlin.
He loves the way in which the serving boy's long fingers graze over his skin when he dresses him; craves the tingling, burning, sensation he gets when Merlin's fingers touch him.
He loves those ears, the ears that he has to stop himself from licking, running his tongue around the dainty shell, each morning when Merlin helps him into his shirt. He loves it when he releases a careful breath across the boy's ear and he visibly shivers; Arthur can practically see the amount of will it takes for Merlin not to whimper.
He sometimes makes deliberately outrageous suggestions, just to see Merlin loose control – to hear him say iArthur /i not isire/i. He loves the sound of that, loves the way Merlin's lips look and move when he shouts out his name. Arthur desperately longs to make Merlin cry his name out, in something other than anger or frustration.
Arthur knows how vehemently Merlin defends his friends, and it makes him feel proud to know that the boy regards him as a friend. He loves the thought of Merlin leaping to his defence, willing to do anything to protect him. He hopes that Merlin would argue for him, with the same passion that he argued for Lancelot; would be willing to die for him, like he was for Gwen.
It is thinking these, and just general, thoughts of Merlin that has Arthur hardening, mind moving to more physical thoughts. He shuts his eyes and imagines Merlin's agile fingers, relaxing his tired muscles with a massage and one of Gaius' soothing lotions. He might be an idiot, but his fingers feel iso good/i when they are slipping over his skin, working kinks and knots out of war weary muscles.
Arthur tosses back the covers and slowly moves a hand down his chest, imagining it belongs to a completely different man, and further down until he grasps his hard cock. He imagines it's Merlin doing this; Merlin's fingers slowly exploring him, mapping every inch of his proud member. He wipes his thumb over the head and through the weeping slit, imagining, longing, iwilling/i it to be Merlin's tongue. And it isn't his fist that's wrapped so tightly around himself, pumping in a steady rhythm, it is Merlin's hot, wet mouth, eagerly swallowing him down.
And next, Merlin would…
The prince's fingers tremble in anticipation as he reaches over to the candle at the side of his bed and quickly slicks one of Gaius' lotions on it.
Merlin must know what Arthur does with the candle each night, he must. The way he leans so close to it when he extinguishes it, lips so nearly touching the wick, he makes the most delicious pout and that's enough to get Arthur hard instantly.
He moans Merlin's name when he slides the candle inside himself, lost in the burning sensation that is somehow so pleasurable. He imagines this is what it will feel like when Merlin first pushes into him; only that will be so much better. Imagines Merlin moaning his name as Arthur clenches around him. Their kisses would be hot and messy; later, as they curl up by one another, there would be time for slow and loving kisses.
Arthur tenses himself around the candle, imagining the look on Merlin's face. He presses it in and out of himself, a slow, steady, rhythm to start with. Merlin would need that, probably wouldn't be able to last long enough otherwise; not on the first time. But then Arthur probably wouldn't either, he reasoned, not after dreaming of it each night – longing for it every time that Merlin looked at him.
He slides it faster now, harder, raising his hips a little to hit ithat spot/i, and crying out Merlin's name each time he does. His other hand is on his cock again, pumping it in rough, erratic movements.
Arthur is so close. He pushes the candle faster, wishing Merlin were here, thrusting smoothly in and out of him; he'd bite Arthur's neck, effectively claiming him, and just grin that ridiculous grin and watch, watch while Arthur came over their stomachs.
He comes with that thought, but is left sticky and alone; he is comforted by the thought that Merlin will have to clean the sheets in the morning, again.
And the next evening, when Merlin lights his bedside candle – fingers curling around it, stroking it almost sensually – it's all Arthur can do to muffle his moan with a gloved fist and send Merlin away early that night.