This story is 100% fantasy.
Part 1
I grew up in a very liberal, free-spirited family. I'm the older of two children, with my sister being two years younger. My dad was 25 when he and my mom got married. She was 24. I was born just over a year later, so my parents were on the younger side when both my sister and I were growing up. I am now 49, my sister 47.
My family lived in a fairly isolated place in the foothills of Northern Arizona. Both my mom and dad had inherited a large sum of money, and neither of them had to work. We were home schooled and did not have much interaction with other kids or families. Our parents lived a very uninhibited life style and were nudists. Being nude was simply how we lived, and never thought of it as anything other than normal.
Puberty didn't hit me until after I was 18. I started to get erections, but had no idea why. I also started to get hair in new places. As liberal as my parents were, they never did give me "The talk."
Shortly after my 18th birthday, my father told me he was going to explain some things to me. He then asked me if I knew why I was getting erections, which I didn't and told him so. He asked if I ever played with my dick when it got hard. I had not at that point, but I asked him why that happened, as it was occurring more often, almost daily. I also asked him why I was starting to get hair around my dick and balls, because no one else, he, mom or my sister had hair down there.