It´s a variation of some children´s game.

All the dancers are in a circle. Every dancer has picked up a card with a certain move on it. Now the dancer is the move. The chorus does some easy movement (or a new one to practise). The teacher starts with her movement for 8 counts and then choose another from the circle for 4 counts (then she goes back to the chorus movement). Now the dancer with that move has to react quickly and do her movement for 8 counts as well. Then she picks up a different one from the circle and so on. The counts are not so important but it will make it quicker.
To make it easier, write the movements on large cards (format A4 or so) so that everybody can see it. The cards are then on the floor in front of the dancer.
I´m really looking forward to it. We´re going to learn interior hip circle this Thursday so this will be my chorus movement. I guess it´s gonna be pure fun :-D