Sherlock stopped moving, looking John in the eyes. His cheeks were flushed, and it was from more than just exertion and arousal.

Quickly, his eyes flitted down, away from John. "I.. I'm sorry.. I assumed again. I know you don't top.Forget I asked." And suddenly, he had ruined the mood yet again. Good going, Sherlock- he thought to himself. You are good at cocking it up.