Hand gestures can be a vital factor in many languages and it is well known that Italian is one of those languages.
A great way to impress students would be to start the lesson by saying:
– Today we are going to learn how to communicate with other people in Italian but none of you is going to need to open your mouths at any moment for this purpose. How does that really work? Well, it is part of the privilege of speaking Italian. Welcome to the family! Let me show you!
Also, if you have someone in particular who is very chatty in your class while everyone else is working, or simply you need to have a quiet moment from the students, you could play the card of ONLY ITALIAN GESTURES ALOUD NOW and everyone should only communicate with gestures until further notice.