The object for this lesson is a can of the cheese that squeezes out. Or you could use any other object that squeezes out of the top like toothpaste or whipped cream or something like that. I would just choose the cheese because you can eat it up at the end of the lesson. Here is the story: Demonstrate how easy it is to squeeze out the contents from the can, then pick a volunteer and ask them to try to put the cheese back into the can. Of course it is impossible. The moral to the story is that angry or sarcastic words or derogatory names can so easily escape our mouth and then the damage is done and we have sinned. It is much more difficult and maybe impossible to fix the damage or repent for the idle or angry words.