Back Sac 

The practice of pulling your testicles between your legs until they become rested on or near the anus. Performed by guys with the name of Chadd.

If you don't quit back sacking, your testicles will become streched out. \

Don't back sac me bro!

Back Sac by Peter Heineken December 1, 2007

Sack to Back or Sac to Back 

Sack to back is the term used when two males ride a motorcycle or scooter together.
Also referred to as "Butts to Nuts"

Those guys are riding "Sack to Back or Sac to Back"

Sack to Back or Sac to Back by Indetrucks March 4, 2011

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 

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

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

Back Sacrificing 

Having to be the one to always lean over the center conceal of the inside of a car to show affection to a female.

Yo, mike that girl had me back sacrificing last night in her Caddy, now I got a torn lumbar!

Back Sacrificing by The Notebook November 1, 2005

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