For this prompt in Kinkme_Merlin: Arthur/Merlin, Arthur makes Merlin lick either his own come and/or Arthur's come off the floor. The other way around -- with Merlin doing the ordering and Arthur doing the licking -- would also be wonderful.
"Merlin," Arthur purred. "You've made a mess."
"'S your fault," Merlin grumbled limply from his place beneath the prince.
"Ah, but Merlin, I believe YOU are the servant here."
Personally, Merlin thought Arthur enjoyed that fact just a little too much. Or maybe a lot too much. He was fairly certain his duties didn't include anything remotely like last thursday's little "chore."
"Prat," He muttered.
Arthur chuckled and Merlin shuddered, the soft brush of Arthur's stomach against his back shivering through his over-sensitized skin.
"Get a move on, Merlin," The prince said, a smile in his voice.
Merlin obligingly (minus a few choice words grumbled under his breath) moved to obey.
"No, wait," Arthur said abruptly.
Surpised by the sudden breathlessness in Arthur's voice, Merlin turned to look at him. Arthur's cheeks were flushed and he looked from Merlin to Merlin's come on the floor.
"I want you to lick it up."
Merlin's eyes widened. He should- He should be disgusted, but...the new arousal in Arthur's voice made heat pool low in his stomach.
"Come on, Merlin," Arthur prompted gently, nearly groaning.
Merlin looked back at his prince again, relishing his expression, then bent and swiped the flat of his tongue over the still-warm come that his orgasm had spilled over the floor. Another lick, slow and thorough. Above him he heard Arthur's breath hitch. He lapped at the floor a few more times, letting Arthur's noises and the taste on his tongue warm him up. He turned and looked up at his prince.
Arthur, dark-eyed and panting, pounced him, pressing the length of his body over Merlin's and rutting against him. Both were already half-hard again. Merlin trembled under the familiar weight, arching up when Arthur's mouth slammed down over his, tongue invading greedily. He didn't pull back until they were both aching for breath.
"Going to make you come so hard," He panted, voice rough against Merlin's ear. "Want to watch you do that again."
Merlin moaned at Arthur's length against his and Arthur's fingers sliding inside him and nodded.
"Want to watch you lick up Every. Last. Drop."
"Prat," Merlin meant to whisper, but it came out, "Yes."