Draco hadn't really known what to expect when Billy sent him that message, but he's hardly bothered by their slight detour from more hellish matters. Briefly he smirks a bit against Billy's neck, a quiet noise of his own muffled there when fingers thread through his hair. Even if he hadn't just said so, it would have been obvious Billy was enjoying it, and Draco momentarily lets himself enjoy the increasingly familiar taste (and smell) of him.

He bites quite leisurely around and up, making slow but sharp progress toward Billy's ear, which he spends some time biting and sucking beneath before he bothers to respond at all.

"Given how much you seem to like this, I'm somewhat inclined to bite you all over and see what happens..." He trails off, his tone shifting from quiet to a lower whisper. "...but what do you want?"