A circle of voices. Sometimes you hear everyone, sometimes only your neighbour — and sometimes the host whispers something in your ear.
Circle:
You can help steer the circle while you sing: switch the mode, shuffle, and speak live into everyone’s ear. The host can open this up for everyone; if you know the PIN, you can unlock it now.
Your voice goes into everyone’s ear as an instruction, over the other voices. The audience doesn’t hear it.