When in an argument over the attractiveness of a female with another female, a man may apply this rule to cement the fact that he's correct.
Women: Wow she is totally hot.
Guy: No, No she really isn't are you bind or something?
Women: No she really is, what's wrong with you.
Guy: Penis Rule *Points to Groin* I'm right.
Women: Damn you got me...
Ugly Chick: hehhh Are you gooys telking 'bout meh???!!?!?