I struggled with my new CPAP machine this year and went thru different mask types on a weekly basis. The nasal mask was much more comfortable but I am a mouth breather so it became an issue of not breathing through my mouth. I looked at mouth guards from my dentist and various commercial ventures but they simply wouldn't work either. Enter mouth tape.
This tape makes it possible for me to use my CPAP properly. It keeps my lips sealed but leaves a little hole in case I need to catch a quick breath, cough or sneeze. It stays on all night, It catches my drool, and it is easy to put on and take off.
If it isn't sticking, it is because you have tried taking it on and off and its "stickiness" is compromised. It has great adherence but doesn't feel like duct tape when you peal it off.
Highly recommended.