Oji-san ga Joshi●sei ni Warui Koto wo Oshieru Hanashi

A high school girl named Ayumu is in a formative stage of her life when she is approached by an older man with a beard, who dresses in a black t-shirt. He takes it upon himself to teach her about adult topics, offering guidance that is unconventional for her age. The story explores this unusual mentorship as Ayumu navigates the challenges of growing up with unexpected influence from this older figure.