Basically, it's a filler; a word used for when you don't know what to say or lost your train of thought; or when you aren't paying attention to a conversation when it comes around to say what your opinion is. It leaves the opponent with a bottomless pit while you slowly back out of the convo PLO Style
Friend: Yeah man the last time I got my freak on was two months ago, it was with this old lady who didn't really know what to do. It was funny how we met etc....
You: (Very irritated) Yeahhh Cruzity (then walk away)
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.