Sage Koundinya II:
Start in Adho Mukha Svanasana, hands shoulder width apart. Step your left foot far forward, past the outside of your left arm, and place it on the floor well in front of your left hand.
Bend your left elbow and twist your torso to the right, dropping the left shoulder and the whole left side of the torso as low as possible on your inner left thigh. Pressing your thigh toward your torso, slide your left upper arm and shoulder as far as you can underneath the back of the left thigh just above the knee. Place the back of your thigh as high up as possible on the upper arm.
Keeping your weight centered approximately between your hands, start to creep your left foot forward along the floor so more and more of the weight of the leg comes onto the arm; let the left foot naturally move a little to the left as you do this. When you can’t walk the foot any farther forward without lifting it off the floor, straighten the knee as much as you can, powerfully reaching the foot forward and out to the left side.
Bending both elbows, shift your weight far forward between your hands until you can lift your back leg. Lift strongly until that leg is parallel to the floor; then, keeping the knee extended, press straight back through the ball of your foot.
Lift your chest until your torso is parallel to the floor, pressing strongly down through your inner hands to help maintain this position.
Lift your head and look forward, keeping your eyes and forehead soft. Breathe evenly. Hold the pose for 20 seconds or longer, then step back into Adho Mukha Svanasana. Repeat it on the other side for the same length of time.