Undersack

The underside of a man's ball sack.

Her tongue gently caressed his undersack as it moved back towards his taint.

by JizzlePizzizle August 30, 2010

Undersack

The male version of cleavage.

Don't show so much Undersack, you'll be called a slut

by Picklei Volcof March 30, 2017

undersack

A synonym for diaper.

“I have to get rid of these dirty undersacks!”

by anonymous March 1, 2023