What is the proper form and technique for performing the yoga pose known as downward dog with one leg lifted up?

To perform the yoga pose Downward Dog with one leg lifted up, start in the Downward Dog position with hands and feet on the mat, hips raised up. Lift one leg straight up behind you while keeping the hips square. Engage the core and lengthen the spine. Hold the pose for a few breaths, then switch legs. Remember to breathe deeply and maintain proper alignment throughout the pose.