This can be a Hello greeting to get in the mood for class or a Good-bye gesture to send students off in a calm way with a good memory.
You say and sign a short rhythm (usually four beats) to a small group and the students sign it back.
Before they enter the room for their weekly Music Mind Games class, these students are taking turns creating a 4-beat rhythm for their teacher, Iván, to sign back to them. Every time he expressed enthusiasm and joy with their rhythms. (Arcos Centro Pedagogico Musical, Madrid)
If this is the last activity, after they sign back your rhythm, you can whisper "good-bye" and give a small wave.
The students will wave and leave quietly.