Him being biologically unable to violently fuck Uzaki because of spirit chains being the only reason the author could come up with that this manga didn’t instantly turn into a hentai when they started dating is so funny.
Imagine an early 20-ish. strait-laced young male adult that was regularly teased by his busty little-imp/kouhai in the past suddenly served his kouhai quite literally on a silver plate willingly on her own wish.
With those 'chains' of self-control gone, no bonk can even stop whatever the kouhai had been nurturing inside her senpai for years.
And no, the chain analogy is just recently shown in this very chapter.