Here we have parents and children working together, but it could be suitable for same age groups as well. One of you holds the pen and is passive, the other holds their hand and takes it and the pen for a walk around the page. After a minute or two swap roles.
It is a really interesting exercise. Dominant personalities can struggle with letting go, and followers get the opportunity to take the lead. Working with families it is apparent that the adult is not always the dominant party and vice versa, so it provides a really good level playing field where we can step out of our usual roles, whatever they might be.