The definition of a cunt sack is a person or object that resembles or acts like someone's testicles or just acting like a
complete cunt as well as a sack of testicles. This can be used as a
description of a man's masculinity or as a woman's fact of being a
fucking whore. Or just your dumbass friend.
Sally: Gee, Matt is sure
being a Cunt Sack today, I wish i could get rid of him.
Ginnie: Yeah, he seems like a
complete dick.
Matt: You are a
fucking Cunt Sack , I'm right fucking here.