I abandoned the story because the FMC seemed a terrible person, I read the comments here and felt even more justified, then I read the chapter and I think....the author should just stick to drawing hentai.
This chapter feels wrong for various reasons
1) It feels a poor excuse for gratuitous nudity
2) It makes the FMC out to be socially stunted, mentally damaged, unable to read social situations and egocentric
3) Her friend is a victim but she too is unable to convey what should be pretty simple to say and dishes out a terrible non advice
This reminds me of a great Manga, 14 Sai no Koi, the two have been a couple for a while now, they felt urges they didnt understand, so you know what they did? They read about it and took it step by step and actually had sex, it had no nudity, but it felt more fullfilling than this nudity, because it was planned (even if their peculiar situation helped them), it was mutual, they wanted it and both understood what they were doing, they went with confidence.
The anime adaptation surprises me, hopefully the first episode turns off people as it should, with this chapter I don't think I can have much faith in the author anymore, 54 chapters, I have seen better series that had to make to with much less.