shake that monkey

The first sense is a reference to the idiomatic expression monkey on one's back.

shake that monkey (third-person singular simple present shakes that monkey, present participle shaking that monkey, simple past shook that monkey, past participle shaken that monkey)

1. (slang, idiomatic, uncommon) To rid oneself of a bad habit or influence.
2. (slang, idiomatic, uncommon) Of a woman, to dance provocatively.