Mary is fucking disgusting and poorly implemented into the story but at this point fuck Nanase, too. Wtf is this dumb "if she was your gf none of this would've happened" shit, lmao. Mary raped Nanase but Nanase was turned into this "go along with everything and think about it later" lame-ass average shoujo babe.
Look at chapter 16 and how she changed from there. She literally shouted that they are lovers and to leave them alone, now she let's herself get fucked in front of her lover and enjoys it, ight. And only after she thinks "this might've been bad and hurt Momo".
This is the weakest "omg realize your feelings everyone" hurr durr bullshit an author has pulled in a long time. No need to force and change every character on a whim to progress. If you suck ass at writing and don't know how to progess just ask to cancel your own series ffs
Momo should just move on to someone else at this point, Nana is trash now.
I agree that Mary is a piece of trash and should not exist at all but...
Please tell me that the word "blackmail" means something to you..
It's one thing to feel physical stimuli and physically react to it and whether you like the situation you're in or not is another separate matter.
Mary managed to take a video of a risque moment that Momo and Nanase are in and threatened them with said video evidence.
Nanase went along with Mary's demands because she doesn't want the video getting spread out into wherever and thus leading into unsavory rumours from the people around them.
You also have to remember that these two are still in highschool. Let alone highschool kids, not even most adults in the West where people are more open and individualistic about things would automatically think "I'll sue you for blackmail!" when being blackmailed.
Considering how important social reputation is for many Asian cultures, you'd naturally want to keep mum about these things.
[ For context as not to downplay the importance of social reputation in many Asian cultures:
You get stuck with it for the rest of your life or untill everyone around you forgets about it (people don't forget that easily).
If you just so happened to be around people very unaccepting of you being different in some way, you're gonna get hounded out for it for a long while. Peer pressure is not a laughing matter. ]
Now, imagine if Nanase did say no to Mary with the mindset of "she won't do it anyway" and Mary actually does post the video. What then?
Nanase might not care about what happens to herself but Momo definitely will care about what people will end up thinking about them.
And don't forget, many unsavory people who have too much time on their hands are loud and active on the internet. If those people happened to find that video and thought it would be a good idea to try something on both of them... Things would go south. Very badly.