Although it was his first time dating a girlfriend... his virginity was taken by her mother. (Kawakami Yu, KEED-80)

Noboru is discovered to be a virgin by Yu, the mother of his first girlfriend, Kanna. He succumbs to Yu's allure, and she goes from kissing and oral sex to deflowering him and taking his virginity for the first time! Although he feels disgusted, Noboru gradually becomes addicted to her mature vagina…