Theres these two girls who i recently befriended at college. I sometimes randomly walk into their room (they live together) and sit down in one of their chairs and go "Heyyyy! Hows it going" and just try to mix in with their conversation. One day one of them said "I think calaris should stop coming into our room, he might rape us". so I went "woah woah you wouldn't do that to me would you" Anyway I'm assuming we have some rapport going.

Anyway there's this other guy who loves to wander into their room as well (very annoying) and it might be difficult for me to compete with him.

Does anyone have any routines or suggestions I can use to be more dominant than the guy and build massive attraction?

Show that you are an alpha male. If ya'll are ever in the room at the same time, befriend him. Trust me, it will disarm him. What you need to do is simply be more interesting then he is. Don't talk shit about him to the girls because it will just lower your value. Yes, you will have to compete with him, but just be more interesting then he is and know how to have a good time and it should do wonders!

-Patience