I'll leave the tutorial for the origami envelope here
https://www.rozeu.co.uk/index.php?route=product/product&path=2240&product_id=54012&language=en¤cy=GBP&plb=pos1
I’d imagine the reason for them not having a relationship is that Chion wants to make sure the Gen sticks around by his own volition after graduating.
It’s easier to imagine if you reverse the genders, for some reason. Somehow the relationship becomes more taboo / you expect Chion to take on a more fostering role.
I think Gen is 17 turning 18 and Chion is 19 turning 20 so the age gap isn't really a big deal. Upcoming chapters indicate Gen gets with her which is...kind of great.
Code:
Mod Note: Please use spoiler tags when talking about chapter-specific or future events.