When my father remarried, I suddenly had a new step-sister. She's plain, wears glasses, and has a gloomy personality. At first, I wasn't interested in her appearance. But one day, I went to her room to have some fun, and I saw her masturbating. What's more, I was captivated by her beautiful big breasts, which I couldn't have imagined from her plain glasses-wearing outfit! I went into her room and helped her masturbate using the toys she had been using, and I was thrilled by how erotic she looked. So...