Find how the chamber vents
Identify the valve before using any pump.
Read the instructions for the exact model
Locate the vent in the maker’s diagram and check the controls away from the body as directed. If the manual does not describe a prompt way to vent the chamber, choose a clearer design.
Distinguish power from release
Turning off a motor, disconnecting a hose and opening an air valve are different actions. Do not assume that stopping the motor vents a chamber.
Stop if anything feels wrong
Follow the maker’s limits. Stop and release the cup immediately for pain, numbness, bruising or unusual swelling. Seek medical care if the cup cannot be removed or symptoms persist.