18-year-old European amateur getting fucked in the ass aggressively

I looked around a skate park today. The boys I saw there were just superb. But I had to be very careful to approach them. One boy was so bad at skating that I had to laugh out loud. He came there with a girl. I thought she was his girlfriend but she turned out to be his sister. Kinda boring. Still, she helped me a lot to talk him into some crazy stuff. For money of course. At first he showed me a few tricks. I wasn´t sure if I should push things further while his sister was still around. To my surprise, she enjoyed convincing her little brother to show me more and more of his body. I guess they liked to tease each other. Her brother was no better. When he agreed to do more intimate stuff, he insisted on doing it in his sister´s room. I hope she didn´t smell my cum in there.