My step-sister had always been sorta close, she was a year younger than I am. My mom married her dad when we were young, I was six she was five. We both had siblings, us being the youngest though we became fast friends. Anyway our parents would bathe us together when we were younger so seeing each other naked was no big deal. When she and her sibling came to visit for weekends or summer vacation she would sleep in my room along with her brother. And I can remember sometimes masturbating after they had fallen asleep and sometimes hoping she'd catch me and.... it just excited me for some reason. So you can say I had a thing for her from the begining.
Anyway my real story happened when I was 12 and Lori was 11. It was late summer and everybody in the family was off doing their own things.... my mom was at work our sisters and brother were down at the lake, so Lori and I were home, my stepfather was outside doing yardwork. We were playing in my room, I don't remember what game, but we got bored. So I believe it was Lori that said let's play strip 21. I thought about it and thought if we ended up naked together it was no big deal, we'd seen each other before. So we started playing.
As we played I remember thinking how excited I was getting. I mean playing a game where the loser took off an article of clothing..... just did something for me. After playing a few hands we started just getting silly. And we ended up just doing strip teases for each other. I was a little shy about taking off my underwear though, because I was quite erect. Lori could see my bulge and wanted to see it. So very reluctatly I pulled my underwear off. Lori had just her panties on and soon she removed them. So there we were, both naked as jaybirds and myself sporting a hard on. Lori thought it was funny that my penis was pointing straight out, and asked if it always did that. I said not always, I was only 12 remember and didn't understand why it did myself. Lori then asked how long it stayed that way and if it hurt. I said no it doesn't hurt, but when I rub it..... it felt good and the stiffness went away. That's when she told me she sometimes would rub her private area and it tickled. We both agreed to show one another, so we both laid down on the floor. Lori spread her legs and started rubbing her clit, I started to rub my cock. Even right now 21 years later the thought of Lori's hand rubbing herself makes me excited. It wasn't long before Lori and I got even more curious and agreed to touch each other. I can still remember her hand softly embracing my penis, she was amazed how it could be hard yet still feel so soft and warm. As she rubbed my penis, I was discovering the female vagina it was very soft and warm. I don't know how long we did it for. I doubt it was too long.... I still don't last too long. LOL. But I remember I dry came in her hand, a short time later her body started to tremble. After we finished, we had just finished getting our clothes back on... our father(her father - my stepfather) came inside. I can't imagine what he would have thought if he'd busted in on us a few minutes earlier. He asked if we were behaving? We said yes.
Lori and I did play a few more times over the next year. But after her father died we didn't see each other as often, and grew apart. I still look back on our time as a positive thing. We were both just two kids just learning about the opposite sex. The fact she was my step-sister does bother me a bit being an adult now. But I tend to believe that what happened to me has happened to others as well(I know some stories on this site are total fantasy, but some are real like mine). It's just how we see it in retrospect, and remember being young is a time of innocence and discovery.
I must admit I did masturbate while typing out my story. It still was my first sexual encounter with a girl and I remember it happily.