Literal Meaning

He talks nonstop like a favorite person reporting somebody at the chief's court

Implied Meaning

A favourite person is unrestrained in the use of words when reporting somebody to the chief. On the contrary, an ordinary person has to use his words guardedly

Origin

If a favourite offends a chief, he is only given a reprimand, but an ordinary person who commits the same offense will either be severely punished or banished from the chief's court