For cupping to be tight, you need to burn the air in the canister well, be close to the area where the canister is applied, and so on. Fire cupping is to burn the air in the canister to make the canister form a negative pressure and thus adsorbed on the skin. 1. The air in the can is burned sufficiently: if the air in the can is not burned thoroughly during the cupping process, resulting in a small negative pressure, the adsorption on the skin will be small, and the can will be easy to fall off. 2. Close to the site of the application of cupping: As the negative pressure formed after the combustion of air in the can is short-lived, generally about 2 seconds, if the site is far away from the application of cupping, the negative pressure will disappear very quickly, which will lead to the can adsorption on the skin. The cupping method can adjust the negative pressure by itself. Fire cupping is a risky operation, it is not recommended that individuals cupping at home, it is best to go to the hospital to find a professional doctor for treatment.