When I was 14 my uncle married a woman who already had three daughters. Her oldest daughter was about my age. I remember they used to come over and visit on the weekends, staying well into the night. Us kids would play games and whatever while our parents drank and played cards.
I remember this one time. I think we about 16, me and their oldest daughter thought we were too old to play games with the younger kids. She and I decided we would play video games in the basement away from the others who were playing upstairs. I got bored with the video game and laid down on the couch with my feet behind my stepcousin. She kept trying to get me to resume play and kept tapping my leg.
She gave me an ultimatum. Either I start playing or she would sit on me. I still told her no, so she jumped up and sat right on me. I don't think she meant to, but she sat right on my dick. This of course got my attention and my dick started to get hard. She of course noticed it growing right away. Her eyes got big and she said "what is that? What are you doing?"
I told her I couldn't help it and it was her fault for sitting on me. That's when she got a devilish grin on her face and she asked if I wanted to stick it in her. I told her we would have to be quiet and do it fast. The game room was right next to the steps and we could hear if anyone were to come down, but we still had to be quiet. She stood up and pulled her pants and panties down a bit. I unbuttoned my jeans and slid then down just enough so my hard dick was out. She grabbed a hold of my dick and stroked it a few time, then rubbed the precum on her pussy. She sat down on me sliding my dick inside her. I remember it feeling really good even though I had already been having sex with my girlfriend. She whispered that I needed to let her know when I was about to cum. I shook my head yes and said okay as she started to move up and down on my dick.
She was sitting sideways on me as I still laid on the couch. So I was able to massage her ass with my left hand while I rubbed her leg with my right hand. Then I reached my hand up the front of her shirt to her tits. She didn't have much, but she did have enough to fill her bra. I first rubbed her through the bra until she told me to go under it. I slipped my hand under the bottom and pushed it up out of the way. Her tits were perky and felt amazing.
I was so happy she had slowed to almost no movement by this point, or shirley I would have finished. She instead was slowly grinding on my dick. I could tell she was enjoying herself as she clinched the couch in her hands. Her eyes were closed and she was biting her lower lip. I'm sure it was taking everything she had to stay quiet. She was letting out quiet squeaks while she was shaking. Then it passed. She once again started moving up and down on my dick until I told her I was about to cum. She lifted up off me and quickly grabbed it stroking me to finish. I had made a mess on my shirt.
I pulled my pants back up and removed my shirt. I quietly snuck out the door and down the hall to the laundry room, rinsing out my shirt and grabbing a dirty one from the hamper. Returning to the gameroom, my stepcousin asked again if I was ready to play. I laughed, and knew that we had been successful at not getting caught. She and I would have sex a few more times after that, but it was never as risky at that night. My uncle divorced her mother when I was in college, so I don't see her as much as I used to.