David says to Jane: "Wow, that John is a really boring guy to hang out with."
(…at that moment, John walks into the room, accidentally hearing the conversation between David and Jane.)
Is there a word for these situations when you trash talk someone that unintentionally/by accident hears what you are saying about him/her?
Edit: added a Family Guy clip for extra context/explanation:
https://youtu.be/5GwAHEgOxuU
Best Answer
David put his foot in his mouth.
The mistake itself could be called a blooper. If you want something more old-fashioned: an indiscretion.
If David wants to express regret for what he said, he could say, "Me and my big mouth."