Ok my story happened when I was 15 years old, my sister who was 14 at the time was really close to me. Almost everyday she would want to sit on my lap, sleep in the same bed etc. Keep in mind a 14 year old girl with a fully developed body can catch a boy's attention quickly,
Well one day she sat on my lap and I couldn't help but get a boner as I felt her soft and warm butt (she was wearing shorts) press against my penis. I was kind of weirded out by the fact that my sister can turn me on by just touching me. Well the next day we watched a scary movie and of course she wanted to sit on me so she did, but what caught my attention was as she sat on my lap, I could see down her muscle shirt. It was a sight I will never forget, she has full perky breasts so it had my blood going.
That night as we were getting ready for bed she slept in the same bed as me, when she laid down she pressed up against my body (her butt pushing my penis) it felt so good it gave me a massive boner. I know she felt it because she constantly pushed in and out basically grinding on my penis. I said 'What are you doing?' she then says 'I can't help myself you turn me on'. I couldn't help to think how wrong is it that we could possibly do something sexual. I said 'Ok, we can help each other out but I'm not gonna have sex with you, don't tell anybody', she agreed and asked me a favor 'Can you rub my vagina?'.
Without question I slid my hand down her panties and began stroking her warm and moist vagina. I know I was doing a good job because she took her muscle shirt off and began quietly moaning. It was intense for me, after like two minutes she grabbed my penis with both her hands and started stroking it with a tight grip. It felt so good, I was playing with her vagina using one hand and grabbing her boobs with the other. I felt the intense pleasure running through my entire body just as I was about to cum she squirted on her orgasm.
She finished and I wasn't done so I asked if I could dry hump her...... she agreed. She pulled her panties up and let me rub my penis against her butt. I did this as I used both hands to grab her boobs. I only lasted about 30 seconds before I felt my cum rushing through my penis and flying out the tip. After my first ejaculation she said she loved being touched my me, when she said that it made my boner come back up. I asked for one more favor 'Just lay there and relax'. I pulled out my penis and started stroking myself as I touched every one of her private parts (vagina boobs etc) as she laid there guilt-free.
To finish I put her nipple in my mouth and began sucking, that pushed me to my limit and I ejaculated for the final time. I wish I could relive that moment. As of today we always give each other that weird look because we both remember but dare not to do it again.