Screenshot survey
Show printed screenshots of the product, and ask questions about it:
“What do you think you do on this screen? How would you do that?”
“What do you think you can press on this screen? What would that do?”
It helps to place the printed screenshots on a printed “tablet” for kids to get into that mindset. In the case of remote sessions, screen share static screenshots or ask parents to print out images beforehand and assist in passing them to their child at the right times.
Why this technique
Asking kids what they think they can do before asking how to do something helps them feel less worried about being tested. Doing so with a non-interactive printout eases any pressure that there is a right answer too, especially if you say you don’t know what happens yet either.