There's a puzzle guide for this and future events you may struggle with:
https://f95zone.to/threads/lessons-in-love-v0-29-0-selebus.48158/post-10318604
Try praying at the shrine 10 times, then see if you can do something else on Sunday.
You have to tie in the 2nd Dorm Wars, then Noriko will try to justify sitting on Sensei's face, Ami will try to say if anyone should sit on her uncle's face, she should, then Yasu realizes that she must as well, lmao.
Edit: There's 3 different ways each Dorm War can end. 1st Floor, 2nd Floor, Tie.