knee-butt

The knee-butt is a painful yet entertaining move that can be preformed on friends and ememies alike. The move is executed as follows:

The unsuspecting victim is standing so that their back is facing you. Approach the person, call out "knee-butt!" and knee them right in the ass bone. Hurts like hell. It is customary to call out the knee-butt warning before kneeing. When knee-butting friends it is recommended to knee with care, due to the potential anal crushing power of the move. Grabbing onto the persons shoulders can add a more visually dramatic element to the move, as well as increasing the power behind it.

Kevin: "Dude why are you hopping around and holding onto your ass like a fucking fairy?"
Steve: "Dustin just friggin gave me the worst knee-butt of my life!"

knee-butt by Lee T September 24, 2005

Knee Buckling Butt Fucking 

This is when a girl is getting fucked up the ass so hard that both her and the person fucking her knees buckle from the forces of fucking and getting fucked. Best observed in any porno where anal poundings are involved.

Dude me and my girl were fucking, it was Knee Buckling Butt Fucking night, she was so tired after that she fell asleep with my cock in her ass, what a night!

Knee Buckling Ass Fucking is the way to go

Knee Buckling Butt Fucking by Overloard October 15, 2010

Buttknee 

The anatomical marvel when a human being has his or her knees located in his or her butt.

The baseball team sat down when they were told to take a knee; they must have buttknees.

Buttknee by Walker Ward August 6, 2012

buttknee 

A spotty ass also known as buttknee, or in a more descriptive way, acne on your bum that you get from sitting down. This is caused from not smoothing your bum, some are even born with it. Name is Butt Acne

"Your ass is well spotty and bumpy you must have buttknee"

buttknee by BussyBaka69 January 7, 2022