I used to believe that the size of a grown up boy's penis is really the same size as a 6 years old one, tiny. I've never seen neither in movies nor in real life a grown up's penis until I met my 1st boyfriend at the age of 16 and was absolutely shocked. I told him, "there's no way I let this inside my house.."
A childhood belief about rude bits

others believed things like this
- I used to believe that gay sex involved a man sticking his penis inside another man's penis.Anon
- I used to believe that grown-ups were born "grown up" and that I would stay a little kid forever.— Still A Kid
- I thought grown ups were born grown ups.— mea
- When i was a nipper my mum told me that condoms were sweeties for grown ups - i believed it for years!! :-)— LCF
- I used to think that Frankie Avalon sang, "Hey Penis, Oh, penis..." instead of "Hey Venus."Anon
- My Sister Once Said That Polly Pocket Was A Real Girl That Got Shrunk To Doll Size And Turned Into A Doll.— Jamie