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-in-law! The summoned skilled succubus Eri (succubus name: Eririn) is confused about having sex with her son-in-law, but he can't resist the temptation of her well-bred Musco and exquisite body fluids. Forgive me for graduating from virginity...