When you hook up with a chick at a
party, you bring her into a dark room, proceed to fuck her, and half way through (or if you are really quick) tell the girl you’ll be right back, leave for a sec, then allow your friend to enter and proceed to fucking her. Warning: Room must either be extremely dark or the girl must be drunk enough not to notice the
change.
Optional: Get your friend to wait under the
bed and after fucking pretend u dropped something while you go under the
bed and your friend proceeds to fuck the girl