Banging or having sex. But before you finish with the person your banging, you must yell out MORTAL KOMBAT! and either the person your banging or your friends, preferably your friends, must yell out FINISH HER! Then you must preform some sort of cool move resembling one from mortal kombat, this move must involve your semen.
"Wow i cannot belive you challenged Nora to sexual combat, what was your fatality"
"I totally threw some semen in her face....just like sub zero"