The patient lies on a board and is partially or fully inverted allowing gravity to apply gentle traction to the spine releasing pressure on the tissues and structures of the lower back. (sportsinjuryclinic.net)
Alternatively, you can manually release the pressure by opening the vent; again the silver indicator will go down when pressure has been relieved. (thefamilythathealstogether.com)
Then release the pressure, take it out, and squeeze the mucus out of the bulb onto a tissue. (parents.com)