When a guy has blown his load up a girls ass the spunk dribbles down to the girls pussy and then 9 months later a baby is born - the bum dribble baby is born!
When your father fucked your mother in the arse to prevent her getting pregnant. However his cam ran out her arsehole, down to her cunt and here you are... a dribble bum baby. Commonly used as an insult
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.