It is always useful to remind ourselves of basic aspects of our t'ai chi.
Actually they are not so basic.
Here is some advice from John Kells.
"Yielding requires correct posture."
"Different cultures have different approaches."
"When standing to attention, the belly is drawn down and up. this brings the lower spine in, straightening and expanding it."
"The spine between the shoulder blades is straightened when the heart are pulls down, up and out."
"The neck is straightened when the eyes pull down, up and out."
None of the above is achieved by straining or using force.