Ancient alternative medicine where cups are placed on skin of back to create suction, to help with blood circulation, reduce inflammation, to relax muscle/connective tissue. Two types of cupping, wet and dry..  Both techniques require a flammable liquid like alcohol then set it on fire then as fire goes out, the cup is placed upside down on skin to create the suction for improving blood flow.  Its one of the most used techniques to relieve chronic back pain.