To make a stress ball, slip a funnel into the neck of a sturdy balloon. if you want to make a firm stress ball, pour flour, baking soda, or cornstarch into the balloon. if you want your stress ball to be softer, use lentils, split peas, or fine play sand. you can also mix a little rice into your filling if you like. diy stress balls: funnel cornstarch into a balloon (optionadd water to the. A stress ball is a fun and malleable toy that's roughly seven centimeters how to make a balloon stress ball with cornstarch in diameter and is a great tool for portable stress relief. both adults and children squeeze the toy in their hands, moving their fingers around to relieve muscle tension, stress, and to exercise the hand. beyond being a toy, stress balls have been known to make people feel relaxed and lower blood pressure. A stress ball is a fun and malleable toy that's roughly seven centimeters in diameter and is a great tool for portable stress relief. both adults and children squeez...