These names are plays on words to get gullible folks to say "My Cock's Small" or "My Cock's Long." Either one works on a fool.
*Mike Oxmall can also be spelled "Mike Oxsmall for more subtlety.
Chad: Oi mate, I changed my name to Mike Oxmall.
Bradley: Hi, Mike Oxmall.
Chad: You muppet.
Bradley: What?
Chad: Mike Oxmall/Mike Oxlong
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.