The act of taking a shit on a woman's chest, then pushing one's face in between the shit covered ample breasts, and rocking one's head side to side while making a rapid lip moving motorboat engine sound.
Similar to a motorboat with the addition of the feces.
Did you motorboat that girl with the big tits?
No man, I had the runs so I did a mudderboat instead!
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.