A fork of Rural Dictionary
A Ba-dong-a-dong is a sexual slur that has risen in the past few years and has spread to various parts of the USA. In singular form (Ba-dong-a-dong), it is referencing a penis. In plular form (Ba-dong-a-dongs), it is referencing either just the balls, or the "whole set".
Dude, when I saw her, my Ba-dong-a-dong went huge!