... it's actually Kasumi who first says something like this out loud (or possibly even here, if you want to take it this way).
But this stuff is the bread and butter of comedy manga and anime since, I don't know, roughly 1970. So some people say it's more meaningful here than the typical throwaway gag. Alright. But those who says it's just the same as always have just as much of a point.
Oh, it certainly is a common comedy element, I agree. Which is a big reason for why we overlook this, especially at the start of the series. Probably didn't even take her talk with Sakurako's mom too seriously, at least at first. But seeing them now acting still pretty much the same, but at the same time clearly not intent on separating ever, it's quite reasonable to at least suspect she may have been even just a little bit serious back then as well.
And I just realized it's not just the words... Kasumi is also the one to start clinging to Sakurako first, not the other way around, even if she may say it's for warmth. :D
But whether there's more to this or not at that point doesn't even really matter. It just shows that they have had this very comfortable relationship from the start and probably not even they can clearly say when exactly it became something more serious. It's clear on the first Valentine's Day that they don't see themselves as a couple yet, but it is the moment they notice they're not that different from one. In the end their current relationship is something that just naturally came to be over time, slowly growing during their time together. Often between chapters, as already the next month on White Day we see things escalate again.
last edited at Mar 15, 2019 3:14PM