Watch your mouth!

watch (one's) mouth

To be very mindful or cautious about what one says; to control what one says in order to avoid offensive language. Watch your mouth! I don't care how you speak at home, that's not how we talk here. After being threatened with detention for my snide remarks in class, I knew I had to watch my mouth for the rest of the semester.
See also: mouth, watch
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Watch your mouth!

 and Watch your tongue! Watch your language!
Inf. Pay attention to what you are saying!; Do not say anything rude! Hey, don't talk that way! Watch your mouth! Watch your tongue, garbage mouth!
See also: watch
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

Watch your mouth!

and Watch your tongue!
exclam. Pay attention to what you are saying!; Do not say anything rude! Hey, don’t talk that way! Watch your mouth! Listen, potty-mouth! Watch your tongue!
See also: watch
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
See also:
References in periodicals archive ?
Speaking on my behalf, I would to like to tell those insult-mongers, "Watch your mouth!"
Watch your mouth! I say this as a friend: You violate other people's rights and antagonize certain people with false information and slander them with the scenarios you make up in your mind...
WATCH YOUR MOUTH! Len and Angie Spain, of Willenhall, Coventry, are warning of the risks of oral cancer caused by smoking