The marks, as if you've been hugged by an octopus, are perfectly round little bruises. Cupping promotes the circulation, lymph flow, and energy flow in the local area. It is used mainly to treat pain syndromes, bi in Chinese Medicine, specifically those caused by wind damp. (Wind damp pain is the variety that responds well to heating pads, hot showers, and warming creams.) Pain and tension in the shoulders and low back respond beautifully. It can even be used for cough and congestion.
Suction and silicone cups on the market make cupping comfortable. You can adjust the suction to the patient's comfort level. There still may be bruising, which arnica or Traumeel cream can be applied to. Cups applied to local tension in the shoulders or upper back can feel wonderful. You only need a few minutes for relief, and for some signature cup marks.
Fire cupping involves glass cups, and a lighted alcohol swab on hemostats. The lit cotton is inserted into the cup, removed, and the cup placed on the skin. The heat only causes suction, it does not make the cup warm or hot, so there is no worry about skin damage. Glass cups have a smooth edge that can be moved across lightly lubricated skin (light layer of massage oil) to have a deep tissue massage like effect.
Have an achy back or shoulders? Ask your acupuncturist about cupping.