Binged in a few days Isekai but the guy has a chance to return to his original world if he succeeds? Regular dude who consumes too much erotic content gets summoned to a magical world of Nuns. He is asked to provide "sexual guidance" to 4 goddess candidates as they are potentials to leading the new world. Each chapter is the MC teaching the girls about intimiate sexual acts to broaden their experience and horizons. Sure there's a lot of naughty stuff, but it's also fascinating to see how the common sense of the girls are vastly different. The world or "island" they live on have no menat all, so the culture clash is unique.
This manga isnt' just smashing and dashing, it's pleasure with a decent story.