Ikenai Nanako-san

Aoi loses his virginity after having sex with a woman in her forties whom he met on a dating site. Unable to forget her, he promises to meet her again—only to discover, to his shock, that she is actually his aunt!?

An illicit and seductive love story featuring a mature woman at the peak of her allure, illustrated by Asagi Ryuu!

(Source: Dmm.com)