Top definition
The medial side of the scrotum; the part of the nutsack that connects into the grundle.
Man, I was jibbing that rail when I slipped out and hit my backside ball bag.

Dude, quit being such a backside ball bag.
by Dave C of Windsor MA November 02, 2005
Get the mug
Get a Backside Ball Bag mug for your Uncle Trump.