Adam's Sweet Agony (悶えてよ、アダムくん)

Storyline

Set in a world where all of humanity has become impotent due to the aftereffects of a pandemic, it depicts male high school student Kazuki, the only human with a healthy lower half, living a throbbing harem life surrounded by kind, friendly upperclassmen, unsatisfied female teachers, the academy’s prince, an affluent family’s young lady, and other girls in an academy full of women.