Happened at a end of school swimming party my big sister put on at our house.
It was in early June and school had let out for the summer. My big sister invited a bunch of her girlfriends over for a swimming party. We had a big swimming pool in our back yard. I was 15 at the time and my sister was 17.
I joined them at the pool. But, ended up with the views I was seeing getting to me. I couldn't help it and ended up getting all aroused and ended up with a big boner in my swim trunks. There was no way I could keep it down with all that female flesh around me. A bunch of 17 and 18 year old girls wearing the most skimpy bikinis you could imagine.
Of course; it happened. Some of the girls noticed it (my boner). They started giggling and talking in each others ear as they looked down at my trunks. I then looked down and saw just how much it showed and quickly jumped in the pool. The girls kept looking at me and talking and giggling.
Then, two of them got into the pool and they both walked over to me with these little smiles on their faces. I didn't know what to think. They got to me and one said 'We saw what we did to you. I bet you'd like us to play with it a little bit, wouldn't you'? I didn't know what to say. Of course; I did but couldn't say yes. I looked over at the other girls and saw that my sister had gone into the house. It was then that one of the girls reached down and started touching my boner through the material. Her hand felt so good touching me there. She ask 'Feel good'? I couldn't answer. But, I did let out a groan and closed my eyes.
She then said 'Come on. Let's go to utility room'. We got out of the pool and both girls led me to the utility room out in our back yard. We went in and she closed the door and turned on the light. She then put her hand down into my trunks and started rubbing on my boner. She then pulled them down. There I was standing in front of two beautiful girls showing my cock to them and there one of them was rubbing on it! Before long I tensed up and with a grunt I started shooting my cum. It flew over to the leg of the other girl and she laughed as she rubbed her fingers into it.
I then put my swim trunks back up and we all headed back outside and got into the pool to rinse the cum off everything. My big sister just looked over with a big smile on her face. I'm sure she knew what we had done.