Cupping is an ancient technique that involves attaching jar on to the skin by way of a vacuum. The underlying tissue is raised, or sucked, partway into the cup. Its purpose is to restore circulation, help relieve pain and pull toxins from the body tissue. You will feel a tight sensation in the area of the cup. It often feels very good on tight, achy muscles. The cups may be left in place for 5 - 15 minutes. Cupping causes the skin to turn red, blue or purple, especially if there is an energetic blockage under the cups. The skin discoloration may last anywhere from a few days up to two weeks.