Mask Madness

I have been a CPap user (ResMed 11) since June. I'm over the initial bumps and challenges and have had very high scores on "MyAir" app every morning (90-100) I started using the new auto temp/humidity hose last week and have changed my pillow (for my head) to one of those that allows me to sleep on my side. (Not a real fan) That said, I have noticed recently that while I seem to be well connected to my nasal pillows "mask" my mouth is full of air. Put another way, the Cpap is providing air to my nose and somehow to my mouth. I have an appointment with the Resp Therapist in a week but as this is a new development and it occurs to me I may have changed something or I'm doing something wrong that may be causing me problems. My buddy said I should consider a full face mask but I can't see how that would make a difference. Thanks!

When the back of the tongue touches the soft palate, it closes the connection
between the airway and the "foodway". It is like a "Y" shaped intersection
where the throat connects with both the mouth and nose.
There is voluntary control over the muscles back there, so we can breathe either way.
It switches to automatic without our command, when needed.

As CF suggests, you can block air off at the back of your mouth. Try putting the tip of your tongue behind your upper front teeth. Then position the main part of your tongue up against your upper palate. Finally, give a little suck or swallow to create a bit of suction. You should now be able to open your mouth while breathing entirely through your nose. Practice this during the day, and see if you can get it grooved in deeply enough to help while you are asleep at night.

Miss Emerita's suggestion worked for me, though it took me a couple months to train my body to seal up all night. So if OP is having trouble getting it to work, keep at it. Rome was not built in a day. Persistence is key.