"button your lip" in Chinese (Simplified)
闭嘴保守秘密
Definition
让自己安静，停止说话，尤其是关于秘密或敏感的事情。
Usage Notes (Chinese (Simplified))
属于非正式用语，有时带幽默感。用于劝别人保密或不要再说话。比“闭嘴”语气更缓和，但仍然直接。常和“关于某事”搭配使用。
Examples
You must button your lip and not tell anyone the secret.
你必须**闭嘴**，不要告诉任何人这个秘密。
The teacher told the students to button their lips during the test.
老师让学生在考试期间**闭嘴**。
If you hear something private, just button your lip.
如果你听到私人内容，只要**闭嘴**就好。
Come on, can you just button your lip about it? It’s supposed to be a surprise!
拜托，能不能**闭嘴**别说？本来是要惊喜的！
My brother is terrible at keeping secrets—he can never button his lip!
我哥哥一点都不擅长保守秘密，他从来**闭不住嘴**！
If the boss asks, just button your lip—don’t get involved.
如果老板问，**闭嘴**就好——别参与。