This happens when one very lethargic testicle does not drop at puberty, resulting in one testicle that is small, deformed and unnattractive. One can still procreate, yet finding a woman that will have sex with a freak of nature is always hard.
Nicole: I was giving Johnny a BJ and I felt a small raison were his left testicle should have been.
Mandy: Are you going to keep dating him?
Nicole: Ja right, he can take his mutant lazy nard to some other chick. I'm out.