Mouth tape
Product
Worn during sleep to improve sleep metrics and breathing
"Drink a 16-ounce glass of water in the morning before you have a cup of coffee — with your mouth tape, of course, on your sleep metrics because you have to have a competition with your wife on who's winning the sleep score."
More source quotes
"One way of training yourself to do this, it's very goofy, is to use that little piece of tape. Start off with 10 minutes in front of your computer answering emails in the morning."