close your lips then put your tongue on the roof of your mouth using suction to "glue" it, then try to make a double chin, you'll feel the bottom of your chin above the Adams apple go up. To make sure you did it right rub your fingers there to see if it went up, it should feel like an indention in your chin. Keep doing this until you feel comfortable doing it as you may not be able to breath good at first, over time your throat will change shape so you can breath better. Make sure you keep a complete vacuum in your mouth and breath through your nose or it won't work. Depending on your genetics you could see results in a month to over a year. Or just don't do it you don't have to.
