I know that mooning is done all in fun, especially when kids do it. However, I was taught never to "show your ass" because it means to reveal your stupidity. My dad would say "his ass is showing", meaning that someone was revealing how stupid he is. After all, an ass, related to the donkey, is considered to be a stupid animal. (My apologies to all donkey lovers. LOL)

One of the places that I used to frequent when I dated a biker had a waitress who would show her breasts whenever the train went by, which was often. She'd run out onto the patio and lift her blouse for the engineer to see but, of course, the bikers got a free show, too. She eventually tried to get all the women present to follow suit. I can see how such things could easily get out of hand especially when there's alcohol involved.