Definition: You stick your toe inside your partners rectum and they clench their anus together as tight as possible. You then proceed to drag them across the room by your toe.
Its some thing you do to one of your friends as a joke and beleive me this shit is funny / you walk up behind them when they are not paying attention and you grab there balls from behind and pull them on to their face because they cant put there hands up to catch themselves so they fall on there face.
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.