Metal is one of five elements in the daoist elemental theory. The five elements are earth, water, metal, wood and fire.
Metal is dense and heavy and pulls inwards. You can think of metal in the form of a sword, carving limits or creating definitions so that we can understand what we are looking at. Metal discerns.
The large intestine absorbs (takes in) water and electrolytes while at the same time allowing waste material to pass through for elimination.
The large intestine or colon starts at the bottom of the right side of the abdominal cavity. The small intestine connects to it there. It runs up the right side of the body to the outside of the small intestine, loops and crosses to the left side of the body under the liver and stomach and above the small intestine. It then passes down the left side of the body where it connects to the colon.
The meridian for the large intestine originates at the index finger. (It connects from the Lung Meridian there.) It passes up the back of the arm along the outside edge.
At the highest point of the shoulder (where the shoulder blade connects to the collar bone) it splits in to two branches. One passes within the body to pass through the lungs, diaphragm and large intestine. The other passes up the neck, across the corner of the jaw bone and cheek.
It passes the lower lips and gums and then doubles back to pass through the space between the bottom of the nose and the upper lip where it crosses to the other side of the nose.
It meets the stomach meridian there.
You can also begin to open the meridians of the inner legs at the same time by doing this posture with the legs spread and the knees pointing outwards.
Note that this posture streches the LI meridian at the shoulder. It also stretches the triple heater and small intestine meridians.
Visualize your lungs and your large intestine. Imagine that they are connected and see if you can "sense" the connection within your body.
Imagine the connection extending to the point of each shoulder.
From there imagine the connection extending along the back of the arm along the outer line to the index finger. Also imagine it passing up the neck, crossing the corner of the jaw to pass into the lower teeth can gums and also back tracking to circle around the upper lips to the opposite side of the face.
Each time you exhale, imagine the exhale filling your lungs and large intestine.
Imagine the exhale traveling up the back of the arm and up the face to the opposite side of the body.
Meditate on both the lung and LI meridian.