Arthur licked Merlin's lips cautiously, but Merlin apparently had no patience for Arthur's hesitance. He pushed his long fingers into Arthur's hair and wrapped his own tongue around Arthur's, pulling it farther into his mouth. Arthur groaned into the kiss and Merlin, encouraged, tugged slightly on his hair.
Arthur took a few steps forward, forcing Merlin to take a few steps backward, until Merlin's back hit the nearest wall. Then he undid Merlin's belt and slipped his hands under Merlin's shirt to feel that warm skin under his fingertips.
Merlin hummed against his lips and Arthur took another brave step forward, slotting his body against Merlin's. Merlin pressed into him, rubbing their chests together and brushing the top of one leg just teasingly against Arthur's crotch.
Arthur broke the kiss with a gasp and moved his lips quickly to Merlin's neck, eager to taste and explore every inch of Merlin's skin. Merlin tilted his head slightly and sighed with pleasure when Arthur's tongue brushed across his Adam's apple. He moved his hands slowly down Arthur's wide, strong back, until they reached Arthur's round, firm behind. He squeezed gently and Arthur huffed against his neck. Merlin smiled and squeezed again. This time Arthur leaned harder into Merlin, pressing Merlin into the wall and rolling his hips meaningfully into Merlin's. Merlin let out an embarrassing whimper and squeezed Arthur's perfectly shaped ass harder, pulling Arthur closer.
Arthur licked his lips and then attached them to a spot just above Merlin's collarbone. He sucked roughly on the skin and Merlin arched into him, their half-hard cocks sliding maddeningly against each other. The friction of their trousers made Arthur detach his lips from Merlin's neck with a groan. He moved his hand to Merlin's waist, eager to get his manservant out of those clothes.
Merlin cupped Arthur's face and brought him back up for a kiss. Arthur bit Merlin's lower lip and dipped his hand into Merlin's trousers, but his progress was halted by a knock on the door.
"No," he pleaded into Merlin's mouth.
Merlin smirked and wrapped his fingers around Arthur's wrist to keep it still. They waited for a moment, Merlin rubbing teasingly against Arthur's thigh, but then there was another knock.
"I have to," Arthur muttered, pulling away. "I - will you be here when I come back?"
Merlin pretended to consider, then leaned forward for a brief kiss. "If you want me to be."