This is honestly the tool I use most often. These cushions are like magic for children who have trouble sitting still like those who have ADHD or are just more active. Each cushion has 2 sides: on is bumpy and one is smooth. They usually come with a pump to inflate them and I like to keep mine about half-way full. They’re easy to find on Amazon and are usually about $20. I’ve had parents buy their own for taking their children to restaurants and they’ve reported lots of success with them.