The woman in the long skirt is incredibly naive about her precautions against showing her underwear! HUNTB-508

My stepsister, who came from my parents' remarriage, is a lovely and honest girl with many friends. However, her friends are incredibly promiscuous; it's unbelievable they're the same age… One day, as I was contemplating these indecent things, my stepsister, soaked to the bone, came to seek shelter from the rain on her way home from school! Seeing this aroused me! Perhaps she's grown up, but she noticed my erection and started teasing me. I couldn't take it anymore! I blurted out my long-hidden desires!