Absorbing, and spinning out of the way of an incoming energy...

Used appropriately, with absolute perfect timing, this half spinning manoeuvre by the defender can be a great defense to a partner's straight arm punch. It leaves the defender in a great position to counter another attack because the defender will end up facing the blind side of the aggressor's body. The defender can also mount an offensive strategy (which could be the most appropriate defense). Adding a step forward after the stabilized end position, the movement can be a repetitive practice for developing a smooth transition into a variation upon Part the Wild Horse's Mane.

Remember: when practicing with a partner,  the one who advances makes her movement precise, clear, strong and keeps the speed of the movement  consistent through many repetitions. Later on, she can disassemble the variables and play.

Let's dissect the movement.

1. neutral position: relaxed, rooted

The pelvis is the level platform that shifts from side to side through the function of the ball joints in the hip. The ground, legs and pelvis are a parallelogram. The level pelvic platform supports the spinal column  naturally with the least effort. Starting from a neutal position, shift  the weight from the centre point-vertical line-midpoint-between the knees to the the left leg/foot. The weight shift goes totally through the point of support which must be directly under the Centre of Gravity: in this case the left foot. 

Now, it is most important is to sense the central pillar about which the body rotates. You the viewer of these pictures can be the cooperative partner-aggressor, who will smartly approach with her right fist,  right arm horizontally extended at the blue shirted fellow, wanting to 'walk through'  blue's right shoulder. If Blue doesn't move, you the viewer will knock him over, so....Blue shifts his weight to his left foot which becomes Blue's new centre of contact with the ground.

Blue swings the rest of his body through a vertical axis which is his left foot. His left hand and forearm rise up to meet the viewer's incoming right fist. Blue's left hand/forearm is NOT A HARD KARATE -LIKE BLOCK (because there are no blocks in tai chi), but meets, contacts, and rides the incoming movement of the viewers right arm/fist, absords and neutralizes it. Blue maintains a safe personal space...a non contact space between his own left arm and his chest...and allows the viewer's arm to penetrate the space that Blue's right shoulder no longer occupies. Can't touch what's not there!

2. left hand/arm begins to receive incoming right fist

3. right hand/arm moves into tickle position 

Blue's left foot/leg is a maypole, around which Blue's hips/upper body spins.  Blue's right foot retreats behind the body and gives the spiral manoeuve the torquing power to shift the length of the right side of the body out of the way. Of course all these actions are acting in a perfect world simultaneously, so even the rotating momentum which raises and stabilizes the left arm into a receiving position... perfectly times itself... to absorb the incoming energy.

4. all the weight on the left foot, toe points forward

5. the rooted body: right arm in tickle position. receiving palm
faces inward, back hand faces outward

The right hand is the only part of the body that Blue must physically lift and place into position. The movement of the body spiral swings the left arm into its dynamic position to receive the viewer's incoming right arm. Blue's right hand is in tickle position. What does that mean? Tickle position? It's a good idea to actually move the right fingers. Loosen up. The right hand can protect the left elbow, further defend against a secondary facial attack, be in position to apply a press....the possiblilities are many.

Finally, the two of you can swing from left side to right side back and forth...tick/tock....tick/tock....tick/tock. 

Notice the forward foot points ahead,
the back foot has swung behind
in a semi circle and points approx. 45 degrees

And now look at a swing back/right avoidance: same movements but around a different center of gravity and the right leg becomes the maypole.

In play, it's really important to be relaxed and rooted in the neutral position.

If you have an expectation that your partner is going to touch your right shoulder with her right fist, and in your mind you are setting up a swing left/rear avoidance, and instead she sneakily approaches your left shoulder, you will get stuck in the middle trying to go both ways at the same time. (Of course, she's not supposed to do this in initial practice, but this is playtime!) You thought that your thinking, your mental preparation, your 'setting of the muscular gain' would gain you a momentary advantage in reflex reaction time. Now you have to release motor neurons on one side of your body before you can activate the other side to avoid her approach. Way too slow. You are caught in a  motor neuron chaos.

So, each time, start fresh in a neutral position: relaxed and rooted. No expectations.