My cousin’s 13th birthday

I was 15 and she was 13. It started in December on her 13th birthday. I’m her cousin, and we live pretty far away. I only get to see her once or twice a month. We are very close though. She invited all of her close friends, and me. I only knew one of the people there, so the party was pretty boring for me. I just played games on my phone. Then as the party was winding down, and most the people left, they decided to move to where I was so that they could include me. I was sitting in the middle of the couch. Then my cousin’s two best friends came and sat on the sides of me. My cousin had nowhere to sit, so she sat down on my lap. Since we were so close there was nothing really weird about it. But while was she talking with her friends she was moving around. I was getting hard from this. She was wearing a thin miniskirt, and i was only in shorts. I was almost fully hard. I didn’t know what to do, so I just sat there and tried to ignore it. I decided to move since I couldn’t make it go away. Then as I was moving she jumped. I was scared she noticed I was hard because of her. so I shoved off of me. Everyone looked over at me, and I tried to play it off like a joke. Then my cousin looked down, and she said what’s that. I looked down. My cock was very clear through my pants. They started to giggle, so I tried to hide my bulge. Then she told her friends to hold me down and in place. She moved closer to me, slowly.
“Alex, why do you have a bulge in your pants?” She asked.
“Well you were rubbing me down there was your butt for the past 20 minutes.” I told her.
“Hannah, can I see it?” Her friend Amy added.
“Not before me, He’s my cousin, I want to be the first one.”
“Fine, Abby, pull his shorts down with me” said Amy.
My cock was twitching all around because I was so hard, and horny.
“Woah, it’s moving all around, why it doing that?”
“It’s because I’m really horny.