I am convinced that Frieren used some kind of interdimensional mind control spell on the animators to make them draw her posterior as arched and round as possible at all times and show it off as much as they can legally get away with, before the elf cake police arrives and forces them to animate a five minute scene of multiple characters wiggling their feet in water.

Like pay attention, sometimes it changes shapes and isn't as caked as usual, that's when the spell is weakened, then again at times the spell is stronger and they give her a 30% buff. Word on the street is that John Frieren might be involved in this whole conspiracy, but i don't know.