One day, at school, it was discovered that I was a virgin, and after being ridiculed, I came home depressed. Then, my cute little sister came over and said something terrifying. "Hey, hey, big brother... are you a virgin?" I was so shocked that I thought about masturbating and going to bed, but the next moment, my sister said something unbelievable. "... I'll help you get rid of your virginity." From then on, I was completely at my sister's mercy...