When I was around six, I heard the expression "pop her cherry" or something like that. I thought it meant that girls were born with their labia stuck together and that the first time they have sex, the penis would break open the slit.
A childhood belief about rude bits

others believed things like this
- I used to believe that if someone had sex more then once a night they would break there penis and die— Chris
- whenever i heard a melody, i thought it stuck in my stomach when i heard it in my mindAnon
- i used to belive when i got an erection that if i bent my penis it would break like a bone— beep41
- I used to believe that you could break open the Television and get the toys— Certeria
- i used to think boys were born from men and girls were born from women— swag lad123
- I used to believe (about 9) that a penis was a sausage that men stuck in their crutch area to attract women.— Feebs.