Takashi, who is adolescent and has a strong libido, believes in the information on the net, endures the masturbation ban for 72 days, and summons a succubus with a secret spell. But for some reason, the succubus that appeared in her flash was just like her mother! The summoned skilled succubus Eri (succubus name: Eririn) is confused about having sex with her son, but he can't resist the temptation of her well-bred Musco and exquisite body fluids. Forgive me for graduating from virginity... Ever since the day I summoned the succubus in a ritual, Erin has been appearing everywhere even though I didn't call her. She appears from under her desk while studying and plays a tutor, and has sex in the pool under the blue sky. One day, Takashi finds a hickey he made on her mother Eri.