The action that results in having a roommate that is either extremely attractive or plays for a school's football team, and picking up the woman who hang around him that he doesnt want.
Dude, my roommate brings the hottest girls to our apartment. I'm bound to get some proximity puss
The fourth man is the person who simultaneously tosses salad and licks the sounddock in a sounddock salad.
This is often used as a hyperbole.
I would rather be the fourth man the rest of my life than help you with your math homework.