(noun) A strange and rare condition where the affected has one large sac and testicle in place of a penis. Always coupled with Penis-Nuts.
a: I saw Martin showering in the locker room today. that ball-cock really freaks me out.
b: I know, it's just not natural.
a: Makes you wonder, when he gets a boner, is it in the penis-nuts or the ball-cock?
b: Truly one of life's mysteries.