Slip of the tongue!

I always try to set a good example for my kids. I take care of myself, work hard, volunteer at church, their schools and treat others the way I would want to be treated. I don't make a habit of using inappropriate language but it does slip occasionally when I'm frustrated.

Yesterday Trey was playing with the sled and Santa. When the sled fell over Trey said, "Damn it" Darnel instantly looked at me, because he knows that is what I say when I break something or am frustrated. I told Trey that we don't say bad words and that nice little boys don't talk like that. I always ask him to tell me what I said, so I know he heard me and understood what I said. He said, "Don't say Damn it"

Does he understand? I'm not sure since he did say it again without a second thought.