When I was young, my parents divorced. I had been living with just my father, but he remarried. My new mother 'Ruka' came into our lives. Ruka was young and had large breasts, making it hard for me to know where to look as someone who likes big breasts... One day, thinking the house was empty, I was masturbating alone when Ruka saw me. However, she did not flinch and instead guided me to orgasm with her large breasts. From that point on, my stepmother 'Ruka' and I crossed the line and began our forbidden sexual activities.
