(So shortly after their fight-like almost right after, I'd say this happens like-in the hall when Yuki goes to make tea-the two of them actually make up to each other)
(So then the next day they go to exchange poems, and Naruki's is the 'I'll be your beach' poem, which is very obviously about somebody else-most likely MC-chan. So Yuki gets upset because he's jealous, and Naruki gets upset cuz he doesn't get why Yuki's upset, and the two fight again a little, which feeds into the animosity later when MC-chan has to pick one of them to hang out with over the weekend.)
(OH I FORGOT TO MENTION-they end up walking home together after they share poems on day 2, so they bond walking home together.
So then for the sake of this one because I think it makes sense-
MC-chan ends up picking Naruki, and the two have their lil date thingie, and then right when Naruki's about to kiss MC-chan-Satori shows up. And Naruki sees the way MC-chan and Satori look at and treat each other, and the way they are and realizes that he will never, ever, be able to compete. So he, without even fully understanding why, ends up going to Yuki's house in tears, and Yuki comforts him and ultimately ends up confessing his feelings, which Naruki ends up returning.)
(So they end up spending the night together-take that how you will Idk-which is why they end up being late to the festival. Neither of them even wanted to go in the first place, so they end up just staying together and just trying to avoid their problems, happy with each other. And they end up staying together and being wholesome with each other, all while in the actual game, Satori is fuckin' hanging himself and Moniko's being a bitch.)