The picture here shows me and Colin starting the movement "Six Sealings and Four Closings" from the Laojia Yilu form.
One of the problems I see in a lot of beginners, and even people who have been in the arts for a while, is a lack of peng throughout the body during movements or postures.
It is not just a problem in Taiji, but I also see it in students doing Xingyi and Bagua.
It is common to see someone in a yang movement with the "attacking" hand, and the rear hand has lost its peng. It is limp. There is no "song."
The word "song" to me means "a relaxed state of readiness."
I recently saw a Yang-style practitioner doing the Yang 24 form. He did "Brush Knee Twist Step" and his lower hand was held with fingers pointing downward. There was no peng in his hand and it was hanging limply with the fingers hanging toward the ground.
I pointed out that if his hand was this way when someone kicked him, he would have some broken fingers.