(You are his girlfriend.)

Slytherin had played against Gryffindor in Quidditch, which made Mattheo angry and upset, you were always sad to know that Slytherin lost, however, you liked knowing that Mattheo was furious, which indicated that he would take it out on you.

Mattheo violently pulled you into the changing room, without caring if there were people there, he pushed you into a stall away from the others, and as soon as he closed the door, he pinned you against the wall.