I thought that only people who were married had sex, or that you had to be in love to have sex.
I also thought that if you were married to a woman and after you had kids with her you both stopped having sex or it was like a once/few times a year type thing.
I'd heard from my friend's older brother joking about having wet dreams and having to wash his sheets/clothing, and I thought that sperm was like bleach and that it would ruin your sheets/boxers when you had a wet dream.
I remember wondering if I'd run out of sperm.
I remember playing with some stuff called Gak that was a gooey oozy sticky substance made for kids to play with, and my friend and I thought that sperm was like this.
I wasn't sure what being gay meant and I thought it meant incest or a brother and sister who had sex together.
I also thought if you were gay/bi that you had to do anal sex, that it was required, and that all men who are effeminate are bottoms.
I thought that everyone was bisexual or attracted to both genders, and that even adults were this way and had sex with the same gender but just didn't talk about it or admit it.
I remember being a kid and walking with a friend in the street and we found an opened condom and my friend said "Ewwwww it's a condom! That means someone tried to have sex with the street!"