Learned this at Kani Club.
In pairs, one person (The Giver) mimes giving the other a gift. Her mime should show some quality of the gift -- size, weight, temperature, value, etc.
The Receiver receives the gift in kind (showing its weight, etc) and identifies it. E.g., "Oh what a beautiful lobster! Thank you so much!"
The Giver, in the spirit of "Yes, and...", follows the Receiver's lead, adding some detail about the Gift. E.g., "I pulled it up in the trap this morning and thought of you."
The mood here is one of generosity, mutuality, giving/receiving, acknowledging. In that way it reinforces the "Yes, and.." ethic of mutual support and inspiration.