All Movement Coming from the Waist (Dan dian)
This movement is fajin or a quick fast Tai chi but you can clearly see the waist leading the movement in the arms. Moving this way we call unitary movement. Moving from the arms first is a segmented action. For power unitary movement is necessary.
Whole Body Spiraling
Silk reeling is a further description of the unitary movement discussed above. As the dan dian initiates the movement it sends a spiraling movement through the torso and then down the arms. At the same time it sends a spiral down the legs through the feet. This constant unified spiral movement is a feeling that is going on every moment in Tai Chi.
Whole Body in "Peng"
(Muscles Stretched 2 ways and Relaxed)
Peng is the state that is created when the muscles, tendons and ligaments both stretch and relax to form both a relaxed and firm state throughout the whole body. Peng is a foundation for the connection so that as you move unitary through the waist and spiraling through the whole body, the actual type of tension promotes the connective motion through the body.
This fundamental state is developed throughout the years of practice to make a more perfect body that can cause better circulation and better unitary coordination.
There are many more "feelings" in Tai Chi, but these are the major ones that when done together produce a most unique and distinct action.
For students who are also in the Chinese Boxing, the lift of the head is altered in combat due to practical considerations at close range. The root is the same and necessary for the encounter closing and control. The unitary is necessary for power movements and the spiraling helps the unitary and can also be use for escaping and reversing various grappling actions. The Peng state is also used in Chinese Boxing fluctuations between a firm state for striking and a loose state for defense maneuvers.