Sitting on the coals
As a Chinese idiom, Pinyin is Zu ò y ú t ú t à n, which means to describe being in an unclean environment and being defiled. From Mencius Gongsun Chou Shang.
explain
Charcoal: a dirty place. Sitting on mud and charcoal.
source
Mencius Gongsun Chou Shang: "to stand in the court of the villain and speak with the villain is like sitting on the throne with the clothes of the court."
usage
The verb object type, with derogatory meaning, is used as predicate and attributive.
Sitting on the coals