A buttsack is when you have very lengthy balls that enable you to stick your sack up your butt, usually is done with maple syrup to make the feces that rub off on it taste better.
I'm on point with my buttsack!
Did you seeHenry's buttsack today? It was covered in feces {:
so basically its like a ballsack but one nut is in the front under the shaft and the other one is in the back towards the anus. also called a buttnut. if you were to shut your legs the buttsack nut would be visible from the back while the normal nut is in the front still.
“tie his legs up and tickle his buttsack when he’s on his stomach.”