How to keep a pet rat calm on its back?

To keep a pet rat calm on its back, gently support its body with one hand while using the other hand to stroke its belly and sides, which can be soothing. Speak softly and maintain a calm demeanor to help reassure the rat. Gradually acclimate it to being on its back for short periods, rewarding it with treats to create a positive association. Always ensure the environment is quiet and free from sudden movements or loud noises that could startle it.