The irrational fear of being bald, more specifically the fear of letting people see that you are bald and the irrational belief that you can somehow camouflage the fact through a toupee, comb-over or some other method that people can discern from several miles away.
Marv has the worst toupee I've ever seen, does he really believepeople don't know he's domophobic?
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.