A game popularized by Abe Aylard and Dylan Bolton where you say "Ballsmack" to a friend and they have to bend over for 5 seconds. if they don't, you get to punch them in the balls.
A degrogatory name for another person suggesting that they are a idiot. It can be demonstrated by smacking ones left hand (whilst in a 'wanker' position) with ones right palm.
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.