If Kaisou hasn't exploded by next year Ritsuka will at least cooperate if people insist on throwing her a party, she knew futility when she saw it okay.

Maybe something like... You could take him out to some fancy dinner. Like make it really super fancy thing so that he thinks that's what you were planning all along, you know?

And then when you get home there's a ton of presents and his friends to surprise him!

It might still give the poor man a heart attack, but only a little one!