What does salty egg yolk girl mean?

Salted duck egg girl is a popular word on the internet to describe a girl who looks pure and innocent on the surface. In fact, she is very lustful at heart, but she just doesn't show it. The salted duck eggs here are very vivid. Egg yolk represents yellow and is wrapped by egg white, that is, hidden. Salted duck eggs also represent rotten duck eggs.

Commonly used for corrupt culture lovers and CP powder [1]. Some girls look gentle, graceful, dignified and lovely, but if you open her hard disk, watch her browsing history, pay attention to her post-it notes, read her chat records and go deep into her thoughts, you will find that the whole girl is "rotten" like a salted duck egg, which is full of butter.