here is a group of muscles that run from under the chin and jaw bones down to the front and side of the throat. These keep the skin tucked tightly under the jaw.
As these muscles lose their tone, folds of skin known as ‘turkey neck’ can form and so can a double chin. Keeping these muscles strong and toned will help preserve the definition of the chin and jaw.

As the muscle develops you should feel the muscles tense from under your chin down the front of your throat, under each jaw running down your neck, and in the large muscles at each side of your throat that support the head.
Clench either fist and then use your other hand to steady the fist at the wrist. Place your chin in-between your first and second knuckles. Then tip back your head as far as is comfortable.

Now try to move your head down to look ahead against the upward pressure of your fist. Make sure your teeth are clenched together.

You should feel muscle tension under your chin and down the front and sides of your neck. Try not to let your chin pivot on your knuckles so you begin to look down. You need to keep the muscle under your chin stretched out and under tension.
Hold for up to 30 seconds and then slowly relax. If you do not have a suitable desk, you can push down with your neck against the counter upward pressure of your clenched fists and arms.