According to several Korean business men, a 'Jack Jew' is someone who is a wall street mother fucker, the type of Jew who, unlike his Orthodox brothers (i.e. Matisyahu), do not take their faith seriously. Instead they are fake money grubbing whores.
Korean business man says in think Korean accented English to his friend: "Why you be jack jew with me?! You inflate stock price for going public, make lots of money and fuck me? You jack jew."
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.