@orochijes unlike what hentais say, a girl can't orgasm non-stop for hours. Yes she can go a few rounds but she still gets exhausted eventually.
But the question is do they still experience pleasure from the act, or does the guy continuing to go just do nothing for her at that point? Because if a guy can't keep going, it's pretty much done because the erection stops being a thing, but a woman doesn't magically seal up suddenly, far as I'm aware, preventing further sexual activity. Sure, she's exhausted, but it's not like she necessarily needs to do anything for sex to keep going- it just makes the act less mutual. So long as she doesn't mind him continuing, I don't exactly see the issue of things continuing until they're
both exhausted. It's just that things literally can't if it's the guy that's sexually exhausted first (so long as he can get an erection, that is- if he can stay hard but can't move his muscles anymore, that's different and I'm sure the woman can keep riding him until she's satisfied or he can't keep it up down there).
In any case, I feel like this doesn't take into account the fact that gigolos and male-centric porn does exist already... It's just not as high-profile, I suppose..? Pretty sure these reversed roles in question are also the way they are due to biology- women bear children, thus, unfortunately, carry the greatest burden if things don't stay completely recreational, either by accident or intent. Unless I'm wrong about this, I would think any world where sexuality roles are reversed should go all-in on it. Have humans be more like seahorses in that respect or something.
I also notice there's a currently-running version of this story, with a more refined art style, and the one that swapped places into this world is a friend of the two girls featured in this chapter, Kawashima and Kanzaki.
Kinda makes me wonder what happened to the other version of the main character in this one- did he become the sweetest guy in his own form of paradise, where he's not being treated as a piece of meat and be a rarity among adolescent males, treating women with respect and inadvertently being popular that way?