Stripping off, stay and pick this exercise form (3,3)
I believe the answer is:
tai chi
'exercise form' is the definition.
(type of exercise)
I cannot understand how the rest of the clue works.
(Other definitions for tai chi that I've seen before include "form of self-defence" , "'Chinese meditation involving slow physical exercise (3,3)'" , "Chinese system of slow exercise for relaxation, balance and health" , "Chinese system of self-defence" , "Chinese exercises" .)