Holding a stress (during a yin yoga practice) on a connective tissue for several minutes creates a phase change in the fluids, which results in a lengthening of the tissue and a feeling of ease.
This phase change also allows a greater movement of chi through the tissues, which is both pleasurable and promotes healing.
The power of yin yoga is time and not effort. It takes time for connective tissues to slowly respond to a gentle stress.
It cannot be rushed.
Learning to wait patiently calms the mind and develops the necessary attitude for meditation.