The ZQuiet is worn in the mouth. Right out of the box, there is no adjustment needed. Simply open the packaging, locate the “Size 1” mouthpiece, and place in the mouth. Just be sure to place the top and bottom pieces correctly. The manufacturer recommends that you wear their mouthpieces for about 20 to 30 minutes during the daytime to help your mouth get adjusted to the new normal. MADs like the ZQuiet mouthpiece can cause discomfort and some drooling in the first few days. This is considered to be the “break-in” period when it comes to mouthpieces and is entirely normal. After a few days have passed, you should be able to easily sleep with the mouthpiece on.