Please give credit to: http://en.wikipedia.org/wiki/Gua_Sha
Gua Sha involves repeated pressured strokes over lubricated skin with a smooth edged piece of jade. The smooth edge is placed against the pre-oiled skin surface, pressed down firmly, and then moved down the muscles or along the pathway of the acupuncture meridians, along the surface of the skin, with each stroke being about 4-6 inches long.
This causes extravasation of blood from the peripheral capillaries (petechiae) and may result in sub-cutaneous blemishing (ecchymosis), which usually takes 2-4 days to fade. Sha rash does not represent capillary rupture as in bruising, as is evidenced by the immediate fading of petechiae to echymosis, and the rapid resolution of sha as compared to bruising. The color of sha varies according to the severity of the patient’s blood stasis — which may correlate with the nature, severity and type of their disorder –appearing from a dark blue-black to a light pink, but is most often a shade of red. Although the marks on the skin look painful, they are not. Patients typically feel immediate sense of relief and change.