To teach belly breathing to kids, have them lie down or sit comfortably. Ask them to place one hand on their belly and the other on their chest. Instruct them to take a slow, deep breath in through their nose, filling their belly with air and making it rise, while their chest stays relatively still. Then, have them slowly exhale through their mouth, feeling their belly fall. Encourage them to repeat this process several times, focusing on the movement of their belly. Demonstrating the technique yourself can also help them understand how to do it correctly.