18+ E.R.I.N.A.

Erina Matsumoto is the person every high-school student dreams of being. She is intelligent, attractive, and has a warm personality—the "perfect student," as acknowledged by classmates and teachers alike. However, when Erina catches her teacher Takei in the act of masturbation, she shows her true colors.

Behind the glamorous facade of an honor student lurks the sadistic and seductive witch that Takei comes to know all too well. Having been blackmailed into submission, the teacher must now act as Erina's sex toy lest she reveal the indecent act she witnessed him committing.