There are two basic types of cupping, stationary and moving. Stationary cupping us used to detox a specific area. It is commonly used on athletes who are competing and building up lactic acid (or lactate and other metabolites) in their muscles. With the stationary you will see the customary round bruises.
With moving cupping, we are treating stagnation or lack of circulation. The moving cup is like a modified massage: instead of pushing on the muscles, the cupping pulls on the muscles. This results in increased circulation and healing and reduced pain. Moving cupping rarely causes bruising of any kind.