Fire cupping is a method of acupressure that applies a vacuum to the receiver" s skin. By heating the air inside the cups and then placing them against the skin, a vacuum is created as the air cools. The suction created can be therapeutic or erotic. The air inside the cup can be heated with a candle, lighter, match, or even a cotton ball soaked in alcohol. The trick is to heat the air in the cup without heating the glass too much. To ensure a tighter fit, massage oil or lube can help prep the site that the cup will be applied to. The set includes three cups: small (1 3/8" diameter opening), medium (1 3/6 inch diameter opening), large (6 inch diameter opening).