Why do boys like roommates to bring their girlfriends to the dormitory to sleep?

I think this matter should be analyzed from two aspects. First, I think boys like roommates to bring their girlfriends to the dormitory to sleep. Maybe this boy wants to secretly watch this girl, and also wants to secretly watch them make love together and watch his roommate fuck his girlfriend. On the other hand, he likes roommates with girlfriends, and he wants to secretly watch girls masturbate, so that he is interested. In short, this boy is very scum.