Run (one's) mouth phrase
If you "run your mouth", you talk non-stop and nonsense, especially in an annoying way.
He kept running his mouth until his mom got really angry.
Katherine admitted that her tendency to run her mouth could get her into trouble
The young lady has run her mouth since the early morning.
The verb "run" should be conjugated according to its tense.
A humorous way of saying that what one has said is just what they acknowledge and may not be entirely accurate
Mike: Have you returned from your vacation on the beach? Your skin seems to get tanned.
Jenny: My skin is always dark. That's my story and I'm sticking to it!