A J-system younger sister who still can't stop thumb-sucking. What was once a cute habit now confuses her brother with its eroticism as she grows up. One day, after seeing her brother's erect penis, the sister pounces on him saying, 'I want to suck it.' Her brother then discovers that his sister's vagina gets wet just from giving oral sex, and he can't contain his excitement, becoming addicted to sex with her. Eventually, the sister becomes so addicted to oral sex that she even gets wet while brushing her teeth…
