狐狸未成妖
[hú lí wèi chéng yāo]
It refers to a young fox that hasn't yet become a demon. In Chinese folklore and mythology, foxes have the ability to transform into demons or spirits over time, often with human-like characteristics, and stories about such transformations are popular. The person might be expressing a sense of youth, innocence, potential, mystery, and even some shyness and introversion.