Perhaps 'Mom' opened the door on the last page to inquire whether she should prepare red rice and red beans (those who know the reference will understand).
As stated in quite a few of them martial arts movies I watch even to this day: "Buddha's Name Be Praised." (can always look up the japanese or chinese language term, another time).
Vanilla and Osananajimi always go well together, and I'm always happy to see another release with these tags.
Still, the bit where she says she messes it up on purpose for him to come over? Not entirely unexpected, but still interesting. I'm more amazed that he never realised it until then.
Great ending though. Would have liked to actually see the mother's reaction, but this works too.