I used to think the ball sack was a bladder, it filled up with urine and overflowed through the penis, like a watering can.
I used to claim 'my bag was full' if I needed to go badly.
A childhood belief about weeing and pooing

others believed things like this
- When I was little I thought that my urine was stored in my scrotum until I needed to wee.— Bryan
- I used to believe getting the sack involved being put into a cloth sack.— Wangchuk
- I use to believe that your hair grew because you wash i.e like watering a plant — HJON
- I used to think watering dead flowers would bring them back to life.— Natasha
- I used to believe that as I ate food, I filled up, and that once I filled up completely, I would die. Anon
- I used to think volleyball was actually called "ball-y ball"Anon