You (Draco) were in a heated argument with Harry. One couldn't even go one sentence without interrupting one another.He said a particular something that made you snap.

You slam Harry against A wall, his back colliding with the wall, a little thump could be heard. You felt the cold wall on your knuckles as you held Harry's wrists. Anger boiled inside you, you held his wrists tighter. It wouldn't surprise you if you bruised his wrists.