A nasal prong (16) is structured to be situated on a nasal cushion (20) of a patient interface device that is in fluid communication with a source of breathing gas (32) to provide a flow of gas to an airway of a patient. The nasal prong includes a resilient seal apparatus (36) structured to be deformable between a free state and a deformed state from among a plurality of deformed states. At least a portion of the seal apparatus that is received in a nostril of the patient (44) moves toward the free state and to compressively and sealingly engage the nostril in a second deformed state. A flow channel (52) extends through the seal apparatus, the flow channel being structured to be in fluid communication with the source of breathing gas and to provide the flow of breathing gas into the nostril.
