It was a very slow burn over years with my sister. Yes, you read that right... my sister. It wasn't at all like a porn movie where she walked in on me jerking off and gasped at my cock, and then... We had a very normal upbringing and the usual sibling fights and frictions.

But when we were both going to university, and still living at home (we're two years apart), things started to change. We started to actually talk and hang out downstairs watching TV after our parents had gone to bed. I started to drive her places, to pick her up from her classes. We would grab lunch together. We still had our frictions, but it started to feel like we had a real friendship and closeness that we never actually spoke about. We both had separate groups of friends and dated within separate groups of people.

I don't know how it happened exactly, but one night when we were downstairs and our parents were in bed, we started Truth or Dare. It started innocently enough, lots of eye-rolling and giggling. Neither of us was picking Dare, only Truth. Innocent questions...until she asked (voice suddenly very low and quiet) "Ok...do you masturbate?" I was surprised that she would be bold and ask that, but I said of course I did, and that she should try it too (smiling, joking). To this, she reacted with "Noooo! I don't do that!" But she couldn't hide her smile.

Then she asked, "Is that why you take so long sometimes in the bathroom or in your room?" Very perceptive, she was. I said yes and that sometimes I need to get it out of the way to get on with my day. She said that's going to make things hard when I go away for work for the summer (I had a summer job that took me away from June until the end of August each year).

I said that yep, it would be. But a man's gotta do what a man's gotta do. Then I decided to be the one to be bold, and I said, "Well, maybe you should send me some pictures to help me with that." I said it sarcastically, to have some plausible deniability, to make it sound like a joke.

And of course, she recoiled in indignance but STILL had a smile. "I'm your SISTER! Why would you want that?? I'm your SISTER!" Still acting indignant but involuntary smile...

"Well, you're a girl. You still have all the right parts. You have that skirt and swimsuit and all that. Be creative and help a guy out." Still, sarcasm and joking tone, smiling. Not being serious. Plausible deniability.

"Gross!! You're going to have a really hard time then!" And still, indignant and joking but the smile couldn't be hidden.

We went back to talking about other things, Truth or Dare dropped. I didn't think that much more about it other than it was an interesting little exchange, especially that she had asked me if I masturbated. But I figured that was that.

So away I went for the summer job. This was back in the 90s, before the days of text and selfies. For people under forty, this means that you actually had to write letters to people and send photographs. If you wanted to call home, you had to go to a pay phone and wait your turn to use it. Letters arrived in the mail every day for people. I called home every week, and my parents also would send me written letters. Some would have photos in there of family events etc... Every so often, I'd get a letter from my sister too, all innocent stuff.

Then one day an envelope arrived from my sister. Nothing unusual about that, until I opened it and I realized there was another envelope inside it that (I could just tell from the feel) contained photographs. I knew my sister had a camera, and you could go and get them developed pretty quickly and easily in the 90s.

There was no letter, on the inner envelope she had written "To help with your day. Top Secret." Bang, a hammer to my brain. Mind spinning...

At the summer job, I had a roommate. And he was over on his bed reading stuff. And there I was holding this envelope. What was this?? Did she actually...? Act casual. Just act like it's normal family pictures or something. Maybe they ARE just normal pictures. But then why would she say Top Secret? And she's clearly referring to our Truth or Dare conversation.

My hands were almost shaking when I opened the envelope. Inside were five pictures and I remember each of them as if I were seeing them right now. She had clearly used her camera on a timer.

I looked at each picture slowly, resisting the urge to rush through them. The feeling of elation and thrill was almost overwhelming. I really didn't know what to expect. I was incredulous that she had even taken any pictures of herself and sent them to me. I had never felt so incredulous and excited together at the same time.

The first picture was over her in the family room downstairs where we watched TV together, in the jean skirt I mentioned with stockings, no shoes, a slim-fitting top, and hands on her hips. She was nineteen years old and slim, had small breasts that were just little bumps in her shirt, long red hair, fully clothed, and still incredibly sexy. Her head was cocked to one side, one eyebrow up, and a smirk on her face, a sort of "I'm calling your bluff, fucker" sort of look.

The second picture was her sitting on the couch, still in her jean skirt, legs crossed, stockings, no shoes, hands on her lap. Prim and proper, smirk on her face.

The third picture was her in the two-piece swimsuit I'd mentioned in our Truth or Dare, still in the family room downstairs. It was blue which contrasted strongly with her snow-white skin and red hair. Hands on her hips as in the first picture, the same smirky smile and same incredible sexiness without trying.

The fourth picture was her lying on the couch, left leg straight and right leg bent, looking over at the camera. Small boobs as little fabric-covered bumps. Hands on her belly and fingers entwined. Still smirking

The fifth picture was really a step up. This one wasn't in the family room, she took this one in my bedroom. She was in her skirt outfit again, same hands on her hips pose as before. But... and this is where the hammer really hit me... I honestly didn't know if my eyes were lying to me... She had undone the buttons at the front of her jean skirt and pulled it part-way down her hips. I could see her panties, she was letting me see her panties. She WANTED me to see her panties. No smirk on her face this time. She was looking intently at the camera, her lips were parted slightly and the expression on her face seemed almost hopeful that I would like what I saw. She was no longer being the brat. This was different. This was desire.

THIS was the inflection point. I remember it as one of the most erotic moments of my life. I was looking at a picture of my sister where she was posing and letting me see her in a sexual way. My sister wanted me to look at her in a sexual way, and pleasure myself to what she was showing me. This girl I had known for all our lives, all the family times together, the quabbles and quarrels, was now different to me. We knew this was crossing a line, and it was a line only for us.

I knew how I felt in the moment, but at that point, I wondered how she felt taking the pictures and sending them. How did she feel about waiting to see how I would react? She was bold enough to put herself out there and take that step. She was strong, and that made her even that much more special to me.

These pictures started something that has lasted for decades now. Of course, there is more to tell, but this was the moment. This was the moment I knew that my sister and I had something more, something beneath the surface that we showed to the world.