I can't quite remember. The first time I saw a pussy is when I was around 3 or 4 years old and I though that girl got her penis cut off

. The first time I saw another guy's penis, my dad in the shower

I saw my mom's later, accidentally.
The first time I saw a woman's pussy other than my mother and that girl I thought she had his penis cut off was in a porno at the age of 6 years old. I saw a real one at the same age under a skirt of some girl.
The first time I saw a guy cum (besides me) was my neighborg who was 12 years old. I was around 14 years old at that time. Since I'm straight, but open to try new things, my neighborg and me decided to masturbate together and we did some sort of jacking off race to see who cum first. Obviously, since I was more developed than him, I came first. After 10 minutes later, he came, but in small quantity (because he just hit puberty and could barely see pubic hair on him, so I thought his semen production was that small). He's 18 years old now and we still do it, but very ocassionally. We've never done anything sexual like fucking each other, that's not our style.