Seduced By My Sisters Stepdaughter

It started as an innocent enough evening. I went to dinner at my sister's, and we planned to play a game after dinner. My sister had recently remarried, and her new stepdaughter was home that night. We'll call her Casey, for now. I knew she had just turned 18, but didn't attend the party, because I didnt really know her that well.

When I got there, we finished setting the table for dinner, and my new niece came out and sat at the table beside me. She was wearing a cute top and leggings, nothing overly sexual, but looking back now, I realize that was her first tease. She suggested Cards Against Humanity for the game, and she would giggle every time she got dirty cards, and showed me a few of them.

We had a few drinks while we played, so I wasn't feeling up to driving home right away. I set up a spot on the couch, so I could sleep off the alcohol, and went to sleep. When I woke up, Casey was standing over me, with her phone in hand, and mine dinging on the couch beside me.

"You should check that," she said, "and tell me what you think."

I reached for my phone and put on my glasses, only then realizing that casey had changed into a pair of volleyball shorts that were too tight even for her, and a barely there camisole top.I could feel my cock stiffening, looking up and down Casey's body, until my eyes adjusted to realise that my phone was dinging for about 30 different pictures of Casey wearing lingerie, stripping out of it, and masturbating for me.

I looked up at her, totally speechless, and she knew instantly that I couldn't say what i was thinking. She walked over to me, straddled me, and slowly leaned in to kiss me.

"Wait," I said, "we shouldn't do this." I said it, but even as the words were coming out of my lips, I was reaching out to pull her in tighter. I had one hand firmly gripping her ass, while the other was squeezing her breast, and she was grinding against me.

She leaned down to kiss me, and pulled off her top, exposing her perky teen tits for the first time. "I've been waiting for this," she said, "you're mine tonight." Casey reached down, and freed my cock, which was getting stiffer with every passing second. As she slowly lowered herself onto me, she began trembling and moaning.

I began pushing, trying to get myself deeper inside Casey, when I heard her say, "I can't believe you're the one taking my virginity, I've wanted you for so long.."

"Virginity?! Casey, you can't be serious!" I could feel my cock throbbing inside her, and I felt her pussy trembling, as she leaned down to kiss me

"I am, I was almost ready to give it to my ex boyfriend, until I met you." She was now riding me vigorously, and I couldn't have stopped her if I had wanted to.

Every moment inside of her tight young pussy was ecstasy. Watching her breasts heave as she fucked her uncle senseless, I could feel my cock throbbing, ready to explode.

I gripped the back of her neck, and we shared a hungry, lustful kiss, as she said she wanted me to finish inside her. Hearing that made me cum hard, even calling her name out as I spilled my semen inside my teen niece's tight wet pussy.

Casey sat up, looked me straight in the eye, and said, "we're going to do that some more, right? I know we shouldn't, but I was worth it, right?"

"Of course sweetheart, I definitely want to do this more, we just cant tell anybody, they might not understand..

We've been having sex at least twice a week for the last six months. She has even stayed at my house overnight when her job scheduled her to work two shifts with a short turnaround. That night I fucked her to sleep, and she came back during her lunch for a quickie.

If you guys like this story, I may add more of our encounters later.