Aight, Arata. This shit's supposed to wrap up next year and we're running out of volumes. It's time to start laying pipe. We don't have time for chapters like this that don't meaningfully advance the plot. Just go ahead and start fucking your sisters until one of them gets pregnant. Not like...
YMMV on how big of a spoiler you think it is, but There's no reason not to give this series the lolicon tag. Regardless of whether or not it's the main conceit of the series, it's still a prominent part of it that can't be glossed over.
I know you're being sardonic, but realistically the series should have a lolicon tag and I don't understand why it still doesn't. That would at least warn away some small handful of the puritanical pissbabies who somehow read 19 chapters of this manga but were apparently surprised by this...