When Kazusa saw a message from a student addressed to his teacher, she became jealous. Kazusa, who usually keeps to herself, thinks she can only deeply connect with Sensei if he is asleep. So she attacks him while he sleeps to avoid waking him up and satiating her carnal desires... From that moment on, her desire grows stronger day by day and eventually Kazusa becomes addicted to masturbating while using Sensei...