When I was young I knew that a common euphemism for penis was the word "weiner". Being a logical person I assumed that if a penis was a weiner, then a weiner must also be a penis. One time when I was about 5 my father took me grocery shopping and we walked down the aisle where the cocktail weiners were. I looked up on the shelf, pointed, and exclaimed "Look Dad, its a jar of little penises". I had no idea why he was walking away from me to quickly after I said that.
A childhood belief about rude bits

others believed things like this
- I used to think that Frankie Avalon sang, "Hey Penis, Oh, penis..." instead of "Hey Venus."Anon
- I used to believe that gay sex involved a man sticking his penis inside another man's penis.Anon
- I used to believe that gay guys had sex by sticking their penis in the other's penis.— Fanbrat
- I used to think that I was the only person to have a penis!Anon
- I used to believe that every time you had sex your penis would get ywice as big.Anon
- I used to believe that a boy's penis came out of his bellybutton, so you couldn't see it all the time.Anon