Thanks for the responses. Helpful.
Just for clarification, I don't do Kunlun (have read many books including some of the Damo Mitchell books)... but I read the book by Christensen and one thing it says is to sit on an animal fur/skin. In an article on dos and don'ts it says
"I have been asked by people why we do Kunlun® on an animal skin or rubber mat. (The traditional method was to use deerskin or a piece of large leather, but a rubber mat will also be fine, but not as good as a natural skin.) The answer to this question is that all yogic traditions used the fur for insulation purposes. If you touch the bare ground while practicing, the qi can leak from the lower areas of the body, thereby draining the kidney qi."