With a girl you recently met and things are moving a bit quickly but you want to mutually take a step back and be realistic and allow things to move forward organically:
"Can you promise me we won't say the three little words too soon? I want to be sure we're both ready to say them first."
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.