A large (fat or manly) female that mingles with a group of incredibly attractive women in night clubs. The battle pig will scare away men attempting to interact with the attractive females. The only way to bypass the battle-pig is for a self-sacrificing man to offer himself to the battle pig so that his friends may get close to the attractive females.
Dude, I can't get with that chick with the battle-pig in the way.
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.