Her younger sister, Ria, is a beautiful girl with long, slender limbs, but she's a bit naive. One day, while she was taking a nap, she flashed her panties, and even though I knew it was wrong, I couldn't help but stare at her. Then, when she woke up, she smiled and whispered, "Do you like looking at my panties?", and from the next day, taking advantage of her absence, I was seduced for three days.