Hametsu No Yuuwaku

This story revolves around the complicated and highly sexual relationship between Itsuki and her step-brother teacher, Akito. Itsuki is shown to be deeply attached to Akito, frequently visiting his place and engaging in explicit encounters, though she often teases or scolds him for his behavior. The dynamic shifts when Akito reveals he now has a girlfriend, implying their arrangement must end, which leaves Itsuki shocked and seemingly upset.