It is extremely difficult to take back hurtful words once they have been said and once you've said it, someone's feelings have been hurt. It is much easier to be careful to choose your words wisely and with kindness.
This is useful with a lesson about how unkind words can hurt others and how hard they are to take back once they have been said and the damage has been done.
Have students sqeeze the toothpaste out on the paper plate to symbolize hurtful words that we use against someone.
Then have them attempt to put the toothpaste back into the tube.