Hmmm... let's see here... ah! This should be a good refrence point. Now open wide... ah, there we are... oh... oh my... ew... there seems to be something wrong with your tonsils... what? You had them removed already?.... oh dear...
Maybe it's the sleep deprivation but I think that gaping maw is Marisa's. She's about to eat Patchouli's book since it's about mushrooms, and Patchy thinks Marisa's making a move on her.