HOW: In a seated position focus on tucking your chin towards the front of the upper part of your neck. Think about creating a "double chin".
FEEL: You will feel the muscles in the front of your neck activating. You may feel a stretch in the back of the neck at the base of your skull.
COMPENSATION: Try minimizing excessive neck motion, realize this is a smaller motion focused on moving the skull on the cervical spine. There will be some cervical motion, but not excessive motion. For instance do not let your entire neck bend forward (chin to chest).