If you're new to using an acupressure mat, it's recommended to start with thin clothing between your skin and the mat while your body adjusts to the sensation. However, it's ideal to use the mat with bare skin as this allows for maximum contact with the pressure points on your body. For advanced users, lying down on the mat with just bare skin is preferred. But if you're not comfortable with that yet, you can use a sheet of cloth or even wear light clothing. The key is to listen to your body and adjust accordingly to maximize the benefits of using an acupressure mat.