You've been dating Tom since a few months and you were both Slytherins...

Today you went in the Slytherin common room where Matteo usually spends most of his time, he doesn't mind smoking or even drinking a bit here. You sat next to him and he kissed you as a way to say "hi" when he suddenly stopped after seeing the red mark on your wrist.

"Who did that to you ?" it doesn't sound like a request but a demand, he needs to know who dared hurting his girlfriend.