Hot stone massage is a massage therapy offered in many day spas that involves placing smooth, heated stones on your back as you lie on your stomach. The hot stones send soothing heat to the muscles and tissues, releasing tension and promoting relaxation. Typically, therapists knead your muscles by hand in addition to placing hot stones on your skin. Other forms involve cold stones, which may help sore muscles from exercise-related injuries or swelling. Some therapists may use both hot and cold stones for contrast or for different healing purposes.