Jung did not write extensively about working with the body, but he did address the issue on numerous occasions.
“Whenever you have an argument with yourself, whenever you are making a decision, in order to be far-reaching enough you should consider the reaction of the serpent, of the lower brain centers, nothing can be decided definitely…if that answer is overlooked.
Our unconscious is surely located in the body…the sympathetic nervous system of the body is the organ by which you have the possibility of awareness; therefore you can say the collective unconscious is in the lower centers of the brain, and the spinal cord and the sympathetic system.”
Jung’s Seminar on Nietzsche’s Zarathustra, pg. 174-5
“We cannot rid ourselves of the doubt that perhaps this whole separation of mind and body may finally prove to be a device of reason for conscious discrimination—an intellectually necessary separation of one and the same fact into two aspects, to which we then attribute an independent existence.”
C.G. Jung, The structure and dynamics of the psyche.
“So, one can say it is always a wise thing when you discover a new metaphysical truth, or find an answer to a metaphysical problem, to try it out for a month or so, whether it upsets your stomach or not; if it does, you can always be sure it’s wrong… Of course, it sounds funny, but I start from the conviction that man has also a living body and if something is true for one side, it must be true for the other. For what is the body? The body is merely the visibility of the soul, the psyche; and the soul is the psychological experience of the body. So, it is really one and the same thing.”
Jung’s Seminar on Nietzsche’s Zarathustra
This is an informative article about Jung and somatics: