The cupping procedure commonly involves creating a small area of low air pressure next to the skin. However, there are varieties in the tools used, the methods of creating the low pressure, and the procedures followed during the treatment.
The cups can be of various shapes including balls or bells, and may range in size from 1 to 3 inches (25 to 76 mm) across the opening. Plastic and glass are the most common materials used today, replacing the horn, pottery, bronze and bamboo cups used in earlier times. The low air pressure required may be created by heating the cup or the air inside it with an open flame or a bath in hot scented oils, then placing it against the skin. As the air inside the cup cools, it contracts and draws the skin slightly inside. More recently, vacuum is created with a mechanical suction pump acting through a valve located at the top of the cup. Rubber cups are also available that squeeze the air out and adapt to uneven or bony surfaces.
In practice, cups are normally used only on softer tissue that can form a good seal with the edge of the cup. They may be used singly or with many to cover a larger area. They may be used by themselves or placed over an acupuncture needle. Skin may be lubricated, allowing the cup to move across the skin slowly.
Skin markings are common after the cups are removed, varying from simple red rings that disappear relatively quickly, to discolourisation from bruising, especially if the cups are dragged while suctioned from one place to another, ostensibly to break down muscle fiber. Usually treatments are not very painful.