He’s already getting worried looks from Hermione over the bruises and he considers saying that. It won’t help. "Are you --" Another slide in and he rolls his hips to move with it, shaking with pleasure, words harder to reach than ever. "Are you --" Fuck. "Will you collar me?" It was in the books. A slight shift sets his body off again and he gasps, forcing himself to focus. He’s going to come without permission if he can’t get some distance from the pleasure.