The title of this manga series translates to The World of Moral Reversal. It follows the adventures of an attractive high school girl who gets isekai-d into an alternate Earth. This new reality is nearly identical except for the fact that women are now as horny as guys were in her original world, while the local guys are as prude as pure maidens. The entire society is built around capturing women’s arousal, because they will waste lots of money to satisfy it: advertisement is full of nearly naked dudes with huge packages, most of the porn is aimed at women and focuses on men’s bodies, and even regular TV shows pull off daring camera angles to showcase the physical talents of their male casts.

Our protagonist hangs out with the same two girls she knew from her former world, but in this one they have been transformed into a pair of horny monkeys trapped in a spiral of lewd thoughts, who can’t wait to cast off their virginity to any male willing to give them the time of the day. That’s unlikely to happen any time soon, the same way that female classmates in the protagonist’s former world would be reluctant to engage a pair of virgin males who loudly proclaimed the virtues of some hentai book in the classroom.

The story is a slice-of-life that often feels as if the author made a list of all the lewd behaviors that tend to be characteristic of men in the real world, only to then assign them to women and do some entertaining, frequently funny commentary.

Instead of maid cafes, girls go to samurai cafes where attractive boys treat them like princesses for tips. Girls take off their tops while playing tennis in the school gymnasium to attract the attention of the boys. The manga club in school is made out of awkward female loners who draw hardcore hentai. Groups of girls gathered around desks argue about the most interesting objects with which to penetrate themselves. Girls hate exposing their nudity to each other, not wanting other girls to notice any size differences or skin conditions. Female perverts fly drones over men’s public baths to record the action. Sports events have to deal with female streakers. Girls refuse to talk about female underwear, let alone go on trips together to buy some.

The author justifies the logic of this brave new world by saying that because girls can come far more often than men, and are mainly responsibly for bringing about the next generation, it makes sense for them to be far hornier than men. It’s a matter of survival of the species.

My favorite sequence involved an awkward loner guy from the protagonist’s former world also getting isekai-d to this alternate Earth of horny girls. He immediately prostitutes himself to the protagonist’s friends, whose previously aimless lives from then on start revolving around earning enough money to get back to fucking.

All in all, this series is lots of fun. If you’re about as much of a pervert as I am, you’ll probably love it. Apparently it was made by the same author of Interspecies Reviewers, a manga about guys who fuck monster prostitutes and then review the experience according to the particularities of those fantasy races, or whatever. I haven’t read it yet. But I know that the anime adaptation got taken off the air in the US because it was too lewd. That’s a badge of honor.