One of my friends (Not me, honest!) used to believe that girls pissed out their arseholes, hence the reason why they sat down to pee. He believed this up until Year 8 when the whole class corrected him.
A childhood belief about weeing and pooing

others believed things like this
- when I was a kid, I used to believe that only girls could be my friends and all other boys were my brothers.
— rajat - The old classic by the Go-Go's "Our Lips are Sealed" I used to think they said "honest I see you"— Euge
- I used to believe that the Chinese boy in my kindergarten class flew from China every day to get to class.— Debi
- When my brother was little, he believed that girls peed out of their boobs.— Emily
- When I was a little girl, I believed that all cats were girls and all dogs were boys. :)— Mary Ellen
- When I was little, I believed that all cats were girls and all dogs were boys. Go figure!— Laurie W.