Same aspect to "blue balls," but in female form. When a girl almost fullfills her sexual peak but some asshole decides to cut her short from orgasm. Usually, this type of girl is the shit because she can over-ride the power of how men feel when they get blue nasty balls.
John: Yo I was going down on Steph last night and when I stopped she went ape-shit on me.
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.