Spring Cleaning: Ardha Matsyendrasana

With hand wrapped
It's time to clean out those pipes kids. What better all-natural way than twisting? When we twist we constrict the organs, depriving them briefly of their natural flow of blood and oxygen so that when we undo, new goodness floods into the kidneys, livers, intestines and spleen removing toxins and flushing out the muck.
Twisting is also great for spinal health, encouraging each vertebra to retain maximum mobility and strengthening the spine.
Hooked opposite elbow

To get into Ardha Matsyendrasana or "Lord of the Fishes" pose, begin with your left leg extended and your right leg crossed over the midline to the outer left knee.
Pin down the big toe ball mound of the right foot and fold the left foot toward your right hip (if you have the flexibility--if not, work with a strong flexed straight leg)

Make sure both sitting bones are evenly pressing into the mat. Draw the spine long, stacking one vertebra on top of the next with an inhale. As you exhale begin to turn the torso to the right. If you have open enough shoulders, you may consider hooking the left elbow to the outer right knee. Keep the head in line with the spine. Continue to press the left sitting bone down--it's going to want to pop up.

Don't get stuck here! The tendency in twisting is to go as far as you can and stop.
Continue to draw the spine long with inhales and twist open with exhales.
You may feel quite constricting in the low belly. This is normal and in fact, what you're going for here. Ardha Matsyendrasana is a closed twist, so it tends to feel more compressed.
Stay as long as it serves you, find a neutral position in between (dandasana works great) and then it's on to side number two.