A term that when heard should inspire a sense of OH F**K... I'M ABOUT TO DIE :), it is NOT a sexual term, and essentially means the same as "I will kick your ass, and not in a good way", if delivered with proper intimidation can immediately shut down a bad situation.
person 1: (is stuck in an enclosed space)
person two: should i help him, Person C?
person c: methinks he deserves to be stuck
person 1: If you don't help me, I'm gonna plant my foot, up your ass!
It can mean one of two things :
1. When someone basically shoots themselves in the foot when doing something, screws themselves over, a self-fulfilling prophecy etc.
Or...
2. When you get beat at something or get your ass handed to you by someone in any way, shape or form.
( Note : Check yourself before you screw yourself. )
Simply put, don’t be a foot-ass. Lol.
Examples :
And to think, Tyler thought he was all that and a bag of Pretzels... Boy, what an absolute foot-ass!
Or...
Everything was fine until Phoebe started to shade us around her new friends... She’s been such a foot-ass lately...
Or...
Can’t you go 5 seconds without being a foot-ass?