Japanese, literally translated to "thin hammer". can be taken as being called useless. But in the context of the Naruto universe, it takes on a sexual meaning. so, not useless. but an insult to ones penis
Guy A- usuratonkachi
Guy B- What in the hell did u just say?
Guy A- I just said you had a thin hammer
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.