>>1867518
This is Chapter 13 of the Main Story (specifically Chapter 13-6) which I finally decided to get around to after realizing I've put it off for a while due to most of my Monster Girls not being high enough level for it. They still aren't, to be clear. I'm stuck on 13-7 now, but we'll beat it eventually.

I'm cutting out a lot of what happens here as the story's actually quite lengthy, but basically the group breaks in to a lab base to beat up the scientists who kidnapped Damstor with the help of the Poacher Trio (led by Eloise) due to a shaky alliance and the three-way political war going on in the current country, but after you actually defeat the head researcher and her assistant and the army of demons and robots they had, Kuromi suddenly interrupts Eloise in a fit of panic because she's worried Eloise will steal the protagonist role from the MC and "If this keeps up, sooner or later it'll become [Monster Girl TD: I've become a king and the monster girls are doting on me, and now I'm in trouble!] instead!"

Which prompts the Prince to ask her what "TD" means in confusion, causing Kuromi to yell out >>1867039 and leads to the rest.
So she wasn't just doing this in an event or side-quest, this was in the main campaign, and yes, this means Kuromi is yelling out about the TD Festival's existence while fully voiced.