i used to think that boys penises were hotdogs(i tried to eat one once when i was five!) and that big girls breasts were used to slap bad guys...i believed this until i was around thirteen and tried to slap a guy that tried to make a move on me with my breasts(i finally figured out they like that!)
A childhood belief about rude bits

others believed things like this
- I used to think that girls had "balls" and not boys, and the "balls" were slang for breastsAnon
- I used to believe both boys and girls had penises so i thought sex was when they tied them together.Anon
- when i was younger i believed that when two guys had sex they would sword fight with their penisesAnon
- When I was about six, I believed that boys had buttons on their penises--one for pee and the other for poop.Anon
- I used to believe that babies came from between/underneath the breasts.Anon
- I used to think that the shoulder blades were actually "back breasts".— Kdees