I usually start the hour by asking the kiddo simply, "What would you like to do today?" and we go from there.
I'll offer prompts with the toys, like, I'd like them to tell me a story of what's going on, or I may act like an on-the-scene news reporter interviewing them about the action/story. But it's pretty unstructured and non-demanding.
Often, I sit back and see what they do, with just the toys at their disposal and the therapeutic, safe environment. It can be jaw-dropping!
