When Watson ruts against his back, Holmes can't help it; he gasps, very nearly moans, and he gives up on any thread of conversation. Watson in costume is hardly relevant; what matters is his hand at Holmes's cock and his teeth, too light, not enough. They've been apart for too long because Holmes was being careful, was being weak; he needs more than just those light bites.

"Harder," he gasps, his hands gripping tight to Watson's thighs. "Bite harder. Mark me." Under normal circumstances he'd rather sound sexy, sound in control at least, but he's very nearly begging, or as near as Holmes gets to such things.