a term used to describe guys too shy or nervous to talk to the girl they find attractive.
(from Harold and Kumar)
Kumar: Hey look it's your girlfriend...You actually gonna talk to her this time or are ya gonna be a fuckin Vagina McGinestein
Harold: (rushes into elevator and closes door before the previously mentioned girl can enter)
Kumar: Hey, hey, HEY.(door closes)...You're worthless
Harold: I'm not worthwhile.
The one with the vagina can call said rule and win whatever is being debated. It can be called up to 3 times a day, 4 when it's a leap year, and can't be called more than once in a 2 hour span.
Guy: I love you more.
Girl: I love YOU more.
Guy: Nope.
Girl: Vagina rule! I win!
Guy: Damn it.