Is it an idiom to open your mouth?

Yes Luo Kou Xiaoyao comes from a stalk in Luo Xie's game, the anchor of the glory of the king. The anchor hit a person with Li Xiaoyao's skin during the live broadcast. He said Li Xiaoyao, so netizens called him Luo Kou Xiaoyao, so this is an idiom. Idiom is a unique fixed phrase in ancient Chinese vocabulary, which has a long history of use. It comes from ancient classics or works, historical stories and people's oral stories.