When I was about 5-10, I used to think that when a girl went through puberty her vagina split open, but before she went through puberty it was just a small unopened sack.
A childhood belief about rude bits

others believed things like this
- Premature ejaculation was when you came before you reacher pubertyAnon
- I used to think "premature ejaculation" was a boy ejaculating before he hit puberty.Anon
- I used to believe that circuncision was a natural process and that the foreskin fell off during puberty.— Yure
- up until puberty I thought that my nipple would inflate like a balloon to form a breast— EiEi
- I used to believe getting the sack involved being put into a cloth sack.— Wangchuk
- When I was a little girl, I thought all babies came from 'China' (a Vagina)— Lainie