Miia, Papi, and Centorea's are each touched on, and some of Mero's was just covered in the anime.
As I said, Miia's already gotten plenty of discussion about her biology, same with Suu and now Mero. The preview makes it obvious what they're covering next time, more Miia and Papi.
In addition to what Buff said (the end cards are loaded with details), I now seriously doubt you've read all the manga that has been released.
Again, explain to me how it being a hentai would improve anything that hasn't already been shown? Miia's come close a number of times to simply taking him, and has obviously orgasmed at least once on the show.