Watch the movie

I went to watch the movie. Going downstairs to the basement, I grabbed a beer (beer was the only alcoholic drink we were allowed, it was great that we were allowed anything alcoholic at all) and went to the group room where we would watch the movie. There were only a few others and Nathalie already there. Nathalie was preparing the movie, when I entered she looked up at me and gave me a weird look. I sat down on the last free armchair in the back of the room.
As the minutes went by, only a few more people came in and sat down, filling all the seats. Then Kate showed up, also a beer in her hand, which surprised me, since I haven't seen her drink before. She looked around, saw that there was no empty seat and then walked up to me.
"Hey, John, can I sit on your lap? There's no other seat left."
"Oh, sure. No problem." Actually, it was a problem. After she sat down I immediately noticed my cock twitching. It was the thought of Kate's ass being directly above my penis, that made it jump to attention. But Kate being as she is, I doubted that she would actually notice it or say anything against it, so I just let her sit on my lap.
Then the movie started.

The movie went on and it wasn't as interesting as I thought. Though Kate did shift around from time to time and that made things exciting. After a while, my cock was basically rock hard. I put an arm around Kate's waist and she didn't seem to mind. She even leaned into me a little.

Then it got really exciting. We got to the point in the movie, where the main character works as a prostitute. The movie showed basically everything, so we ended up with not only one, but multiple sex scenes. Looking over to Kate, I noticed how intensely she stared at the sex scenes. She was very interested in it. And her face was bright red. The scenes made her shift even more than before, which made it very exciting for me aswell.