I too have just started with my CPAP in the past week. I have the same problem with expiring through my mouth. I do wear a chin strap now…not sure if that is helping but it seems to. The other thing I did which I’m not sure you’re supposed to do is turn my EPR (expiry pressure) from 1-2. I’m quite sure that has helped & my CPAP Provider did not have a problem with doing that. I’m not quite a week in but was able to wear the nasal cushion mask for 7 hrs last night with only one awakening with the “puffs”. I have not tried tape…seems risky to me. But whatever works is up to individuals.