The Dragon is associated with the Zhen trigram. Zhen represents Thunder. The two Yin lines above the single Yang line represent clouds building for a storm. Zhen is arousing and represents the feet. In the martial arts, it represents the left side of the body and the Upholding palm.
The Dragon is the Supporting Palm with a Single Palm Change. As you exit Single Palm Change, do not put your left hand inside the elbow of the right arm. The right hand comes out under the left arm as the left palm turns over to face down. Hold an imaginary ball with the hands.
We first encountered Dragon Holds a Pearl in the Lion Palm Change. In this change it varies in that you hold the hands palm over palm.
Spread your arms like the wings of a Dragon taking flight. In the Lion you opened the hands as if you were a great lion taking a big yawn. In the Dragon you open the hands as if you are dragon stretching its wings to catch the air and take flight.
Steal a Step with the right foot, Sweep Step with the left foot and walk in the clockwise direction.
Sun Lutang starts the Dragon Palm Change from the Pushing Millstone Palm posture, performs a Single Palm Change, then assumes the Supporting Palm posture to walk the circle in the opposite direction. I prefer to start in the Supporting Palm posture.
Notice that Thunder, the Zhen trigram has two yin lines and one yang line. The Sparrow Hawk Palm change had two yang lines and contained a snapping and chopping movement. Think of the two outstretched arms as clouds floating in a clear blue sky. They do not move until you are ready to perform the change. Then like thunder, your hands erupt from the clouds ready to complete the movements.