I have some half blown up balloons under my foot and I am not trying to crush them till they pop, No, I want to test them. I want to see how much they can take. I begin to ease my toes along one of the balloons and rub it gently with my foot. I slide it all along the bottom of my foot and pinch it with my toes. I do this to each of the balloons, you will never guess which ones passed the test and which ones gave up without a fight.