He didn't know what he expected, but this certainly wasn't it. A quick peck on the cheek at first, maybe on the lips, but no less brief. Something that would happen then they'd step inside, and laugh about silly holiday traditions. Then they would have breakfast, and things would continue like normal. After all, they were just friends. Each with their own affections for someone else, that they (at least Merlin) kept masochistically close, even though they knew there was no chance with that person.
Instead the kiss lasted, and when Lancelot pulled back it seemed too soon. He couldn't make himself move, and he might have spoken but the words caught in his throat along with his breath and heartbeat. Had he stopped time without realizing it? Because Lancelot was staring at him for what felt like an eternity before his hands cupped Merlin's cheeks. Merlin was surprised, but more then willing. He pressed their lips together, a little more certainty behind it this time. Any confusion, or coherent thoughts at all were forgotten. Never mind that Morgana, Arthur, and Gwen were only a room away being coaxed out of the room for a breakfast that Merlin was meant to be cooking.