This is what happened on the beach and unluckily enough my sister saw it!
It started out like regular day at the beach. My sister, me, my aunt and my two young cousins decided to go to the beach. It was supposed to be a warm day so it would be a perfect 10 beach day.
When we got there the family friend Mark ran over to greet us and help us bring our chairs down to the beach. He was a good looking kid and I was 14 at the time and we got along well. He was a year older and was 15 with a nice beach body.
The previous year he had accompanied us on a family trip and we shared a room together. We talked that night about sizes of dicks and all that good stuff. He asked if I masturbated and I told him I always did once or twice a day. He said he did as well and we both asked how big each other's cocks were. He said he had an 8 incher and I responded with saying mine was 7 inches. That vacation he ended up grabbing my dick while we were swimming in a lake and I didnt mind but I really didnt want it to go any further than touching.
Well this summer was quite different and when we made it down to our spot on the beach Mark told me to go for a swim with him. My sister had a crush on him and he knew it so he asked her to join us. She was 15 and him and her flirted a lot. WEll when we finished swimming mark and I went up to tan a bit and laid down on the beach blanket side by side. As we were laying there my aunt and the kids and my sis decided to go for a walk...leaving me and Mark alone. I figured hey he touched me last year maybe I should try something to get this going. So I slowly began rubbing my leg against his only to get an awesome response of him moving his leg all over mine. His hand was lying next to me and was slowly nudging against my waistband area of my swim trunks. I moved up that side of my body and he put his hand down where my dick was. I was already rock solid by this point and I let him feel me around and he went up and down on my cock kind of giving me a hand job. Well the family then got back and he pulled away. Then they all went down to the water so we began our play together again. This time I told myself I was going to touch his. And as he was lying there I slid my hand under his stomach and moved to his dick. It was humongous and it was the first cock I ever touched. It felt so wide and thick compared to my 7 inches and his sack was so nice and big. I gave hima slight tug up and down. Then suddenly my sister said that she didn't feel good as she walked up next to me and began crying a little bit. I was petrified that she might have seen me and Mark so I just laid there thinking to myself oh shoot what do I do.
As we were leaving because she was sick Mark yelled goodbye and we left. on the car ride home my sister was very quiet and didnt talk to me much. I thought maybe that she had seen so I said whats the matter. She said nothing I do not want to talk about it. I said ok and the ride was very silent.
When we got home she said I was gay or some comment like that out loud when I told my mom about the fun we had at the beach. So I the n said okay yah I'm gay and laughed at her. I really was just experimenting but I never told her that. Instead to ease things over I told her he grabbed my hand and placed it there on his penis. She said oh alright well I thought you were gay or something. I do not know if I did the right thing because now me and him don't talk that much and him and my sister dont have anything to do with one another. I want to tell her we were just comparing sizes but I don't know how I am going to say that without her thinking I am gay.