SSNI-721 The three days and two nights where I, the protagonist, only had 'sex' with a female student while her parents were away

My beloved older brother and sister had both left home, and it was my teacher who healed my loneliness—. It might have been only natural for a teenage Shion to develop feelings for an older teacher. Her proactive actions clouded her homeroom teacher's sense of guilt, and over that weekend, the two gave in to their instincts, repeatedly engaging in taboo acts without growing tired of them. A vulgar and obscene three days.