Abstract: A sealing device (20) includes a base (22) adapted to attach at any of a plurality of positions on a patient interface device (8), an arm (26) having a first end coupled to the base (22), and an end portion (24) connected to a second end of the base and adapted to apply pressure to an area of a cushion member (12) of the patient interface (8) device when the base is attached at any of the plurality of positions on the patient interface device.