Adjective meaning consistently and irresistibly interesting. Typically refers to a book that is so well written and entertaining as to be difficult to (literally) put down and pause away from.
Have you read the latest Harry Potter? It's unputdownable.
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.