This got removed from r/sluttyconfessions because they deemed it incest, though the term "step" is only the closest approximation I could give. I guess if it is incestual though I should share it here.

For Christmas this year I (M50) was visiting my sister (F43) and her step-family for the holidays. My sister and her BF with both sets of their kids moved in together about seven months ago. I had not met my sister's new family before her oldest step-daughters birthday party, we'll call her "S". I have met my sister's BF many times before, he's a good guy and we've done some things together and I've helped with a few things in the past, but his kids were never really around when I was. So S's 18th birthday party was a sort of chance to get both families together and introduced properly, I met my sister's inlaws and we met them. At the party S and I talked a lot, she was very cool and we had a lot of thing in common (Down to anime and cartoons, she game me some suggestion and I gave her some.) BUT I'm 50 and she's 18, there is no way it was anything but a young girl being nice to a new step uncle.

Anyway, I was invited to spent Christmas vacation at my sister's and her BF's cabin, (it isn't a little cabin off in the woods, it is more of an old farmstead with about three building that they are converting into rooms for an AirBnB, with lots of open fields around it, a lake/pond, and forest around all that.) Life events as they are for me mean I'm basically single so I'm often invited places so I'm not "too lonely" over the holidays. (It's like my sister thinks I'm no suicide watch or something.)

On Christmas Eve my sister told me to go snowscootering with the kids and a few of the other visitors that were over, while she and others worked on getting dinner ready. We spent about 3 and a half hours out on some trails around the place. S spent the entire time riding with me even though there were enough scooter for her to have her own, but she said her little sister could drive it instead.

When we got back we were all cold and stiff and needed to get ready for the dinner, my room was a private little hybel in one of the out buildings without any other common entry or share facilities like the ones in the barn. I went to shower and get ready for dinner, I had to start a burner to turn on the water heater and the little tanks still takes a while to get warm. S came in while I was waiting half naked for the first of the hot water.

At first I wasn't sure what I should do. She had basically been doing everything she could to say close to me all day, but I honestly didn't think it was more than an innocent thing she didn't realize was making me horny. So when she striped down and got in the shower asking me to join her I didn't say no. She ended up on her knees in the small shower cabinet milking me dry as the luke warm water barely kept us warm. She told me she'd be back later that night for more dessert. Before she got dressed to leave she took my phone and got my number and snapped some photos of herself naked there for me.

That night after dinner and presents we all when to our rooms, I sent her a few messages but she never answered. The next morning at breakfast she sat next to me and told me she'd had so much fun yesterday that we should take some scooters out after breakfast. She kept slpping her hand into my lap under the table, I knew she had more planned than just some snowscootering through the fields but I was a bit cautious because she seemed to have ghosted me the night before. No one else really wanted to join us so early, everyone was tired or getting packed up to leave early for other extended family events.

S and I put on suits and went out, we got around the corner of the garage she grabbed me we started making out, she explained that her sister had kept her from sneaking out the night before and that she knew someplace we could go on the scooters for some privacy. We took two and rode about 45 minutes into the nearby woods were there was a semi-permanent lavvo with a big firepit and some skins in it. We set a fire going and it was soon nice and warm inside. We didn't really wait for it to warm up before we were heating it up too.

She told me that she had a crush on me since her birthday and she had spent all yesterday trying to get me to make a move. She'd gone into my room yesterday intent on letting me do what every I wanted to her, and complained that I was too much of a gentelmen. She told me she didn't care if I had someone or not that we could just be FWB, and that anytime I wanted her just to let her know. I was pretty surprised at the offer, but hell yes.

I left a few days later. S and I had taken every chance we could to get away and explore each other. I was amazed that at 18, S knew how to use her body and what she liked better than more than half the women I've been with in their 30s and 40s. And she admitted to liking men over 40 because they knew more about how to pleasure a woman than younger guys.

On New Years's Eve I was going to be alone and planed to join some friends at a few parties but I got a text from S telling me that she would be in the city at 16:00 and that I should cancel any plans I had and let her be my evenings entertainment. I couldn't say no to that. I picked S up at the trainstation, she was in a long coat, but she opened it to show me she was wearing a lowcut, very tight and shiny silver dress with high heels and nylons and she noticed the affect she had on me. She smiled and gave me a big kiss and rubbed against me. I'm sure we got quite a few looks, I led her to my car where we kept making out. When we started driving she unzipped my pants and gave me the best road head I've ever had. We got to my place, I poured us some drinks and she was out of her dress and showing me her lingerie and the toys I was going to use on her until midnight, at which point she would give me anything I wanted any way I wanted it from her. It was a wild night... well and the next day. She left about 3 hours ago (Jan 2), but I have had many many messages from her detailing things she wants to try next time and showing me the bruises and marks I left on her.