Used in a variety of situations from greeting one another to interjecting with it, used then in times of questioning, to making bad East Coast impressions.
(Greeting)
Roberto: Aye who the fuck!
Joe: Oh shit! Hey man good to see you how's it been!
(Interjection)
Joe: Hey let's go shag your momma tonight
Roberto: Aye who the fuck are you!
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.