I started off by telling them that "there's a time to talk and a time to be quiet" and I won't always be there (or know) when those times will be for them but as their Mother, I have to give them instruction.
I told them about a friend of mine, from back home and reminded them about the last time we seen her and her family. That peaked their interest! :-)
I told them about a conversation that her and I had that day.
I said, "I want to compliment you on something." She looked up with a bit of a surprised look on her face but didn't say anything just waited for me to finish.
I said, "In all the time that I've known you, I have never heard you say a negative or critical word about your husband. I think that's very commendable."
She looked down and then back up at me and said very bashfully, "Well...you know, I've really tried to watch that. See, one time, after my husband started a new job someone asked me how his new job was going. I told them that he was working a lot but that it was a good job and he really did like it. Well, a few days later, my husband came in from work and I could tell that he was upset about something. He looked hurt. I asked how his day was and if something was bothering him. He told me that someone had told him that I had said he was not spending any time with his family and kids. He was so hurt, so I have really tried to watch what I say since then because I would never want to hurt him that way again."
I went on with my kids with Q&A about the dangers of talk! See, my friend NEVER said what got back to her husband. And what she meant as just small talk was twisted into BIG TALK!
Then I gave them the moral of the story (which I've had to learn the hard way!):
Don't give people bullets to shoot you with!
a true story