When I woke up in the middle of the night, I felt something in my lower body and my sister was straddling me with a meaningful smile saying, "Big brother, did you wake up?" Wait a minute! I was still a virgin, but when I realized it, my sister had attacked me and I had lost my virginity... But my sister was more erotic than I expected, and it felt really good. So, although it was a somewhat forceful night-time rape and I lost my virginity, I have no regrets! However, I am a little worried about my sister's perversion.