8n Brakes

Does anyone have a trick to locking the brakes together on the N? With the smaller grandsons would like to be able to lock them since their feet can't reach across both petals. Although might be funny watching them go around in circles :lol: :lol: :lol: :lol: :lol: HUM as long as the moms weren't around!!!Thought about just using wood blocks clamped on but thought maybe yao all might know a better way??