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
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.