This skill is performed in the event that your mouthpiece/regulator starts to freeflow. To simulate freeflow, start by tilting your head down to the right, and with your finger, press down on the purge button to simulate the freeflow of gas for 15 seconds, and breathe normally. Then check your pressure gauge. Always keep a reserve of 50 bar/750 psi of air so that, with proper planning, you can make a comfortable ascent.
If your mouthpiece freeflows during a dive, you now know how to breathe off it. It is best to secure your buddy’s alternate air source because your air will escape quite fast through the freeflow. Check your air pressure, and perform an ascent with your buddy.