Hermione was annoyed enough by his question that she briefly considered going in to even more crass detail, but stopped herself when she saw how embarrassed Antonin was. Being cruel for no other reason than just to be cruel was unkind. Surely she was better than that after all they'd gone through together. He also could've been cruel to her about finding her naked and tied up in Fenrir's bedroom floor and he wasn't. Those sorts of petty games were exhausting for all players.