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.
Hello Jello
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)
Good-bye Jello
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.