The curtain is not fixed
It is a Chinese idiom. Pinyin is w é IB ó B ù Xi ū, which means a taboo word for family lewdness. It's the same as "the curtain is thin but not long". It comes from the book of burying Yang Fei instead of Li Kui's advice.
The origin of Idioms
Wang Yucheng of the Song Dynasty wrote in the book of burying Yang Fei instead of Li Kui's admonition: "Di Mei steals the name of his wife, and Kun Zhong's corpse is sealed by the earth. There is no difference between the curtain and the mat, so the emperor's heart swings above and the heart resents below."
Analysis of Idioms
[synonym]: the curtain is thin, the curtain is not fixed, the curtain is not fixed
Idiom usage
It is used as predicate, attribute and object
The curtain is not fixed
a hoary head does research in the classics -- an aged person still learns - hào shǒu qióng jīng
Entering a room and going up to a higher level - rù shì shēng táng
appear to be tough outwardly , be timid inwardly - sè lì nèi rěn
draw from one to make good the deficits of another - yì bǐ zhù cǐ