Hey Golden!
Thanks for uploading the save.
I had a look and you can get the ball rolling with her while she's doing dishes, you can ask for a handjob or blowjob, and it should increase her lewdness.
It might take a bit of time to level up but keep doing that any chance you get to spend with her and certain dialogue choices.
Doing that unlocked the next stage of the Manga Research Club.
Hope this helps o/