Martin can't help laughing a little at John's initial response, though he softens immediately as his mortification becomes increasingly apparent. He still can't stop smiling, but with John hiding himself, that at least seems harmless enough.

"All right, all right," he says, he hopes soothingly; but he can't quite make himself pull off this line of questioning entirely. If he were wildly off base, he thinks there wouldn't be anything for John to be mortified about, and that only sharpens his curiosity. He hums thoughtfully, stroking his hand up and down John's back.

"You just seemed so..." He fumbles his words a bit, trying not to say 'insatiable' aloud; "eager? Not to mention delighted to find out I was jealous of— wait." He blinks, realizing: that was it. Not his being in a mood and certainly not all the unkind jabs at Norah. He'd been joking, but maybe he was closer than he thought: it was when John guessed at his jealous feelings that his mood spun around completely. Martin stares down at him, his hand going still in fresh shock.

"Wait," he says again. "Not a prat, but a jealous prat. Is that it? Y-you liked it that I was jealous." He says it more astonished than accusatory, but the implication is still there.