Background: Coming from the fact that a pig is generally happier in it's own environment - it's own faeces (Makes tastier and tenderer Bacon and Sausages...)
Def: Where one person is extremely happy in the environment they find themselves in
Parachuting into the Playboy hot-tub and finding that their Sun-tan lotion boy is off for the day and they need a new one to oil them up... Expression comes into play when the job is at least 5 mins underway...
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.