I used to think that boys only got penises after they turned 18, and before that I thought they just had a little flap of skin that opened to let the pee out.
A childhood belief about rude bits

others believed things like this
- I used to believe both boys and girls had penises so i thought sex was when they tied them together.Anon
- I used to think that hot dogs were made from boys' penises.— never eating hot dogs again
- 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 think that you could get a tan if you turned the oven on, opened the door and stood in front of it.Anon
- That boys turned into women when they became adults and girls turned into men when they became adults. Anon
- In 'Call Me Maybe', I misheard 'Ripped jeans skin' as 'Rich cheese skin'. — Carly Rae Cheddar