Talk, right. Jon already thinks he's done something wrong, or ruined something, but he tries to rein that in as Martin gives him proverbial space. How does he articulate this when he never has before?

"I ah--I just don't--" It isn't even that he doesn't get aroused, he does. "I just don't want you to think it's you if I don't--go further than this."

God, could he make this more awkward? There's nothing wrong with Martin. Just with him, maybe.