Back-sack 

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.

Back-sack by J'Nathan Bo'Jingles May 25, 2008

back sack 

the back of your peaches

the back of your nut sack gets hit and your like ahh my back sack.

back sack by S.A.R.S. July 2, 2008

back sack 

an unfourtunate birth defect where instead of having a nutsack next to your tallywacker, you have one on your back

I fell off my bike and my back sack exploded

back sack by ice dragon April 4, 2009

Back Sack 

Male equivalent of the side boob. When someone gets a glimpse of your sack from behind. The worst angle to see balls, which are quite frightening at any angle.

That asshole Carl tricked me into looking at his back sack yesterday!

Back Sack by TheRealMikeD July 3, 2021

back sack attack 

The assault of one's testicles from behind. Generally, the victim is bent over, however a standing attack up the legs is also commonplace.

Often times, the assailant will yell "back sack attack!" either at contact, or after the strike is complete.

Winding up for a kick, Ben positioned himself behind a bent-over Matt. Using mostly the flick of his foot unto the scrotum, Ben yelled "Back sack attack!" before Matt ever got the chance to react. Devolving into his fetal position, Matt sat writhing in pain.

back sack attack by MrPistachio February 9, 2013

Back Sack'n'Crack 

Three words defining the hair removal procedures involved in hair salons of a male from the areas of the carpet back, ballsack and butt crack.

Usually coupled with a hairless jock area.

'You're a fucking hairy cunt'
'No way dude, I'm off on a jolly this weekend at a health spa. As part of the package I'm getting the 'ole back sack'n'crack'
'I hear that'

Back Sack'n'Crack by Krikpoh Kneebracket January 28, 2007

Turtle-back Sack 

When a males scrotum is hard like a turtle's shell.

Man, these tighty whities gave me a turtle-back sack.

Turtle-back Sack by Ank D. Holla January 8, 2009