Damn, I hate this thing. 3 days ago I got this rig and have to sleep with it on my face for 30 straight days so the sleep center can collect the data - if I don't use it, the sdcard will snitch on me. I know it's for my own good, but it's awkward as hell even though it's just the nasal mask. Going to try and sleep now... had to smoke a bowl the first night, I couldn't relax enough to sleep. 
I actually have a much smaller nasal only mask now. The first one they gave me was a nose and mouth mask - I felt like Darth Vader. Even my wife was like, wtf. It's just awkward how you can't open your mouth or the air rushes out. Lol