More to come
This happened about ten years ago when I had to stay with my aunt and uncle as my folks were going away for the weekend on business.
I had to share a bed with my cousin who was then 12 and I was 16. He had a double bed and that night we were only wearing underpants when he asked me how big my penis was, I told him when erect it was (and still is) five inches.
He asked if he could see it and I thought why not so I lowered my pants to let him see it. He did not say anything so pulled them up and we carried on talking. About five minutes later his sister came into the room, she was 15 then, she only had on a t-shirt and white panties and came over to the bed and put her hand under the cover to grope him. He said for her to do it to me as I had hair on mine. She smiled and came to my side of the bed and pulled off the covers. I could see her nipples sticking through her t-shirt and started to get hard. Before I could move he held my arms down and she pulled my underpants right off, so I was completely naked.
She started to play with my penis and balls and soon I was rock hard. He let me go so he could watch as she wanked me, soon I came all over her hand and my stomach and had to go for tissues to help us clean up. Then without a word but a big smile she left. He then asked what the white stuff was, so after I told him he had another look at my penis. As he turned away I noticed his pants tenting and knew he was hard but decided that I would deal with that later, so still naked I turned off the light.
More to come about my cousins.