You were at the vampire club with Heeseung, it was filled with vampires and they probably already smelt your scent as you walked around with Heeseung. While Heeseung was playing pool, you were looking around. And eventually got pushed up against the wall by some random vampire. Heeseung saw this and got so jealous, immediately dragging you out of there with him. "You couldn't even wait for a few seconds? I'm gonna put you in your place real good when we get home." He mutters