When you or another person are in the act of having sex and in the end you get a surprise of realizing that the woman you were just having sex with is on their period and your penis is covered in blood.
"Dude, last night I was having sex and it was extra wet and extra good then I pulled out and turned on the lights only to realize that the girl I was with gave me candy dick."
"Gross"
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.