My Story

Most children are exposed to pornography at some stage growing up. With so much readily available on the internet these days, it's likely to be more common in today's society for children to witness something they shouldn't.
In a time when a lingerie catalogue in the mailbox was a teenage boys material, actual nudity and real pornography weren't common to access for the average kid. With no sitter, and just a younger sister for company most afternoons, I eventually ran out of legitimate things to occupy myself with after school in those few hours of being unsupervised. I eventually stumbled upon the family box of photos. It wasn't a mystery to me, as it was occasionally pulled out to show a visitor family photos. However, I had never explored the contents personally. There was the familiar albums on top, envelopes of photos not in albums below, then I stumbled across some black and white photos of my parents, aunt and uncle in an obvious foursome. These photos were totally graphic in nature, leaving absolutely nothing to the imagination. I'm ashamed to admit that as a horny teen boy, this was exciting and I would frequently masturbate to these photos. As I had no idea of their original order of sequence, I would arrange them in different sequences with a fantasised plot to accompany them. Essentially, I was creating my own i****t porn, for my own pleasure. Eventually, my sister was also exposed to these photos, and witnessed me masturbating to them. Shocked and excited, we crossed our own boundaries.
I can't remember exactly how it began, but those photos were definitely involved. Maybe my sister walked in on me, or I could have even called her in to witness stuff. Whatever it was, it progressed very slowly and evolved over years. I remember showing my fully erect cock to my sister when I was maybe 15. This makes her 11, so it was definitely inappropriate. In no time she seemed interested in watching me cum. I persuaded her to get naked with me, and we would simulate sex with no penetration. This was frequent at times, as it wasn't unusual for it to be daily, or more than that.
My sister was certainly turned on sexually, as she would act inappropriate, would grind her hips with mine, and would get wet. By the time she was 13 and I was 17, we were basically having frequent sexual encounters. Now there was penetration. For a long time it was just the tip, and I would usually cum on her pussy. Eventually, we were having full penetrative sex, and I would cum as deeply inside her as I could. We didn't do everything, there was little to no kissing, she never gave me head, and there was no anal sex. It was fun sex. In many positions, but missionary was most frequently our main position. Being often totally naked on top of my naked sister, and thrusting in and out of her as she met my thrusts, I can remember her moaning and I even think she came a couple of times herself. It was always my aim to make it as pleasurable for her as I could. I would lick and suck on her pussy and clit, to get her as turned on as possible before my cock entered her. We were basically secret fuck buddies. Holding my orgasms off for as long as I could, so I could fuck her for a longer period, there was no better feeling at that time of my life, than to pump my sisters tight pussy with as much hot cum as I could. It's still a twisted turn on till this day. I call it a sickness, but I get almost instantly hard whenever I think back to doing it. I can also cum harder and faster if those taboo thoughts are in focus.
Eventually, a combination of guilt, maturity, internal shame, and gaining our own partners, put a stop to things.
At no stage did any of it feel forced. I admit to being the main instigator, as I can't deny I was oversexed, or obsessed with it.
I know that although I was the main one encouraging it, there's no doubt my sister was also keen on sex. I can say that in the early days of having our own partners, we would still have sneaky sex behind their backs.
It was always sneaky, and always kept a secret by us both from everyone. Eventually after years of keeping it secret, my sister put a negative spin on it in an attempt to keep me from leaving my new wife whom she adored. Leave my wife, and she'll tell. That was her threat that became a promise. I was clearly made out to be the bad guy, and I had apparently forced myself on her when we were kids. I was 21 at the time, so it had been at least a few years since we had stopped. The fact that she had waited so long to tell anyone, was total betrayal and malicious beyond my belief. The fact that I was made out to have forced myself onto her, with no admission of her being openly into it, or enjoying it, ment that I became shunned by anyone who knew (this was limited to family at the time).
Upon reflection, I should have pushed the fact that it wasn't forced, and was just kids crossing the line, and experimenting. I shouldn't have had access to those photos.