Originated from Baseketball when Coop (Trey Parker) when his team was playing the gay team.
Then later, little Joey (the cancer boy) asks what it is.
Coop: Vajoina! releases Squeak as Watson misses his shot. Boos from the fans and the cheerleaders as an ump comes in and throws down a flag on the play Uh... No, that wasn't a gay joke, that was an Australian joke. Aw, aww!
Joey: Wow. I watched all your road games. Your psych-outs are the best.
Coop: Thanks dude. Hehuh...
Joey: Coop, what's a vajoina?
Coop: Uh... So uh, what seems to be the problem... with you, guy?
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.