An individual, usually male, that sits around and drinks beer while watching TV. This person is known to sport a good, if not unkempt and shaggy, beard. They are frequently seen on the couch with a laptop and a beer. Fezziwigs are known to be awesome.
My roommate is a regular ol' fezziwig, all he does is sit around and drink beer.
Or
I'm not going out, I think I'm just going to fezziwig tonight.
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.