Morning!
Basically the plot goes to something similar to World's End Harem, one guy in a school or world where there aren't other men or something about most are unable to produce semen or get an erection, I can't remember exactly.
I don't think it was World End's Harem since (I believe) I watched it on hanime and it was divided in several shorter episodes compared to the 20 something minutes of World's End Harem.
Any help would be appreciated. 🥲