When you or someone accidentally or intentionally rubbed your dick with isopropyl alcohol or pain relieving liniment.
Carl: Why are you walking as if your dick's on fire?
Mark: My girlfriend punished me for cheating by giving me the Cloudy with a chance of HEATballs treatment.
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.