but then she calls another guy to do it with her and also somehow seduce Naruse
What would be the logic of that? This is still a bit more serious than the typical hentai with cardboard characters...
Still, if the author is salty, he may do something stupid like that... I think the end it will be just them continuing the affair and it will be heavily implied that Chinami does the same. Basically the entire plot for 100 chapters compressed into 12. Really highlights how much of a poor writer this mangaka is...