What is Back-sack?
1.
Back Sack is the backside of ones scrotum.
A: Yo dog, I can't believe you just ball-tapped me from behind, you got all back-sack.
B: Ew, check out that old guy's back-sack hanging out of his pants.
C: Check out Katz's shaved back-sack.
D: Mom, Jacob put his back-sack on my face.
See