Addressing negative behaviors in other people’s children is tricky. The sandwich technique is a very subtle and polite way of saying "no". The way in which we express a disagreement or a negative one is crucial, both for us to be satisfied, and for the other person to receive a correct treatment. Every time I say "yes" when I really do not feel like it, I’m weakening my emotional state. So for me the best is always try to keep actions in line with thoughts.
THE THREE LAYERS OF THE SANDWICH
1) The Bread, 2) The Meat, 3) The Bread Here’s how it works.
1. Positive message: "thank you for commenting on the concert, the times I've gone with you I've had a great time ...".