Bruised Knee

Slang for a chicks ass.

Damn, look at the bruised knee on that girl!!!

Knee-Butter

The build-up of sweat and dead skin congealed into a buttery substance. Generally found within deep fat crevices i.e. - knee or elbow area.

It's so hot out, I could slather a whole loaf of bread with my knee-butter.

I need to jump in the shower right quick before the knee-butter begins to solidify.

Wooden Knees

A synonym for being clumsy, often related to ineptitude with the use of one's legs.

"Watch out man, you nearly fell."
"Sorry bro, I got wooden knees."