A woman who "claims" she is bisexual but has never been in a relationship with another woman and just makes out with her "girlfriend's" to get the men turned on when they are around thus getting sexual attention. This gives a bad name to people who are real bisexual's.
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.