Reach back and catch both legs on the exhalation
Drawin in the legs on the inhalation
Relax on the exhalation
Repeat three to six times.
Ideally the feet knees, thighs will stay together although in the beginning it's acceptable if not preferable to allow them to to be a few inches apart.
Drishti (gaze) look straight ahead.
Engage Mula and uddiyana bandha, imagine there is a pea beneath you belly that you are trying not to squab by daring in your belly throughout.
Rather than lifting for the leg or pulling in there is a stretching through the whole body. Because the hand and foot are bound this stretch arches the back and lifts the chest and leg.
drop the shoulder blades down the back to allow the chest to lift more easily and to relax the neck.
In the asymmetric version, ground the whole trailing leg pressing into the mat from the hip to the toes
NB: These are practice notes that will be tidied up and put into the new edition of my Vinyasa Yoga Practice Book along with the current sequences and subroutines. The book can be freely downloaded HERE. There is a page on Facebook HERE with all the latest sheets and updates. This book is in no way a substitute for Ramaswami's Complete Book of Vinyasa Yoga.