This article about the teachings Wu Tunan in the IMOS Journal has an interesting definition of the Taijiquan term song 鬆. It is close to my definition. He also outlines a methodology, and further explains where the beginning of practice is in a rather unique way. Worth thinking about.
Strengthness with a Twist: A blog about internal martial arts, theatricality and Daoist ritual emptiness
Brand New Book: TAI CHI, BAGUAZHANG AND THE GOLDEN ELIXIR, Internal Martial Arts Before the Boxer Uprising. By Scott Park Phillips. Paper ($30.00), Digital ($9.99)
Also buy: Possible Origins, A Cultural History of Chinese Martial Arts, Theater and Religion, (2016) By Scott Park Phillips. Paper ($18.95), Digital ($9.99)