Do not be jealous of your sister. Know that diamonds and roses are as uncomfortable when they tumble from one’s lips as toads and frogs: colder, too, and sharper, and they cut.
There were a couple moments in here that I think are talking about other fairy tales and fables, but this is the only one where I can remember the specific story that it's talking about— and I wonder if every instruction is a direct reference to another story or if they're just so seamlessly interwoven that I can't tell which ones are exclusive to this one