Kuro Ai ~Ichiya Saikan Inkou Rannyuuroku~
Original title: 黒愛 一夜妻館・淫口乱乳録
Gojo Testsuya visited his distant related aunt, Kojin Rikka, to borrow money for the operation of Utsumi Ayaka. She is his childhood friend, and she took care of him like his sister. However, in return for lending money, Rikka ordered him to take beautiful women into the house to train them as prostitutes. Assaulting maids and female students, his hidden power was awakening.