I used to think that there was a bulge in a guy's underwear because their penis had to be all rolled up in a bunch...
A childhood belief about rude bits

others believed things like this
- I used to believe that women got pregnant from rubbing her underwear on a man's underwear.Anon
- I used to believe that if I couldn't suck in my gut anymore, my belly would bulge out twice as much.— Secret
- I used to think that Frankie Avalon sang, "Hey Penis, Oh, penis..." instead of "Hey Venus."Anon
- I used to believe that "utensils" were underwear!— Haley
- I used to believe that gay sex involved a man sticking his penis inside another man's penis.Anon
- i used to belief that tampons were rolled up pads in a tubeAnon