Cupping is a type of Chinese massage, consisting of placing several glass or plastic “cups” (open spheres) on the body. TCM practitioners warm the cups using a cotton ball or other flammable substance, which is then placed inside the cup to remove all the oxygen. The practitioner then removes the substance and places the cup against the skin. The air in the cup then cools, creating lower pressure inside the cup, creating a vacuum and allowing the cup to stick to the skin. Fleshy sites on the body, such as the back and stomach, are the preferred sites for treatment.