Someone who is so beyond useless its almost as if they have penises for tits!
Remove outer layer of clothing and any remaining undergarments only to reveal a set of male genitalia where normalhumans would only have a pair of nipples, example "hey penistits what time is it?"
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.