My little bro used to think when the family dog was in heat that she needed a tampon like the "big girls".
A childhood belief about cats and dogs

others believed things like this
- I used to believe that the heat from the furnace came from hell, and that it was a straight drop there.Anon
- I used to think what heated the food in the pan was the boiling water, not the heat under it.— Mario
- 'I've got candy in my ears tonight, baby'.
~Canned Heat, Jimiroquai.— Nin - I thought that cold was an actual, positive force and not just the absence of heat— terberous
- I thought that the difference between girls and boys was that girls have teeth.
Anon - I use to believe that salt would cool food down while pepper would heat your foodAnon