JUMP-4031 My brother is my onapet #5. Kotone-chan Suzumiya Kotone

Kotone, a cute girl of marriageable age, has a hopeless perverted brother who is always hiding in her house and peeping on her masturbating or bringing her boyfriend over for sex. One day, he sneaks into Kotone's room to try and have sex with her at night, but is found out, and from that day on, the brother becomes his sister's slave, and it seems that his sister is forcing him to perform cunnilingus on her as a daily routine... They say b** is thicker than water, but this brother and this sister are like a brother!