To knock sacks is to slam you and a bros nutsacks together while you are doing double penetration on a girl.
by Willy the Huge October 05, 2017
by Fuckfacemickey February 24, 2017
"hey timmy lets play boot sack!!!" timmy replied "ok but this time we are definetly using your sack and my boot
by BynicalBannon December 25, 2018
That douche deserves to become a New England Hacky Sack.
by Slim Pickensboi March 06, 2009
by Rorogerthatgert August 05, 2017
by Sack King July 20, 2017