A sandwich that contains all aspects of a large dinner.
For instance: With a roast/Sunday dinner, one may put mashed potato, carrots, roast potato, chicken (or whatever meat you have) and possibly a Yorkshire pudding.
The kinds of Grandwiches are endless.
Bill: Man, I just chowed down on the most epic Grandwich!
Bob: ... Grandwich?
Bill: Yeah! The sandwich of all aspects; The Grandwich! It is legion, it does not forgive, it does not forget. Expect it.
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.