I was over at my best mate’s house. He has this really hot sister who is two years younger than I am. One night, when I was over there, I went to the toilet. As I was walking to it, I passed her room. She was naked and it turned me on. I went into her room and she saw me. I just lay down on her bed and she told me to take my clothes off. I did what she said and we had the best sex ever.