My little sister, who lives with her parents and brother, is super cute and has a big ass! She currently goes to a cram school and hires a tutor at home to study. My little sister dotes on my brother and has a strong desire to be pregnant with his child if possible. She releases her pent-up sexual desire every day by masturbating and with her tutor. One day, my brother witnesses his little sister masturbating in his room while using himself as a sexual stimulant...