Brad's Iyengar Yoga Notebook
Sukhasana is the basic cross-legged sitting posture which we use to begin each class.   In the Iyengar system of nomenclature, Sukhasana and Swastikasana are two names for the same pose.
We sit for a few minutes in Sukhasana at the beginning of class to create a receptive mind before beginning our yoga practice.   In Sukhasana, begin the process of involution which you will extend and deepen throughout the class.   Begin to observe yourself inwardly rather than extracting information from the external world with your eyes.
For Sukhasana, fold at least one blanket in half from the storage fold to sit on.   Cross your legs at the mid-shins, not your ankles as is our common tendency.   Your pubic bone and the cross of your shins should be in one line.   Keep your ankles flexed a little so that your feet are on their outside edges, perpendicular to the floor, but relax your toes.   The soles of your feet face to the sides and your toes will face forward.   You should not be able to see your feet since they will be basically under your knees.   Do not have your feet under your thighs -- try to bring your feet under your knees or further forward.
Balance evenly on your sit bones.   With your hands, reach back under your buttocks and manually pull your buttock flesh back and out to sides on your sitting support.   As you do that, also separate your sitting bones.   After you roll your buttocks outward, roll your thighs inward.
If you place your fingers on your anterior iliac crests (the "hip points") and your thumbs on the tops of your pelvis in back, they should be level.   If your thumbs are lower than your fingers, your pelvis is tilting backward.   If this is the case, you should sit on more height, such as another folded blanket.   Your pelvis should be in a neutral position, not tilting forward or backward.   This allows for normal lumbar lordosis, allows your groins to relax, and lessens the effort required to keep your torso erect.   Level your pelvis both side to side and from front to back.   Make sure your pelvis is upright and not tilting back.   Do this every time you sit in this asana.   Without this base you cannot build the rest of your spine and torso structure onto it properly.   This is the foundation.
Your groins must relax and descend.   You may notice a tendency for them to harden and tense to pull your torso forward into an upright position.   If that is happening, take more height under your buttocks until you can sit upright with your torso perpendicular to the ground without feeling your groins tense.   If you're doing the pose to practice pranayama, you especially want your legs to feel as if they're "flowing away from you" without any tension in your groins whatsoever.   This may require even more height under your buttocks than you usually use a the beginning of class.   Your knees should not be higher than your hips.   This is another sign of needing more sitting height.   Also verify that your knees are level with each other.
Take your lumbar spine very slightly and softly inward so that your lower back is concave.   Draw your abdomen softly inward and upward.   Sit high enough so you find you have a good lift your lower abdomen region.   Lengthen the often neglected space between the pubic bone and the navel.   From the right and left side floating ribs to the armpit chest, feel yourself ascend.
Lift your spine and your chest upward and also broaden your chest out to the sides.   Allow your ribs to spread outward with each inhalation and note how horizontal actions of the body foster a broadening of the mind and consciousness.   Move your dorsal (thoracic) spine into your body, but do it without hardening your diaphragm or your throat or eyes.   Breathe in from your back body diagonally upward through your sternum and use that action to help you maintain the lift of your chest.
Place your fingertips onto the blankets at your sides and press them into the blankets with your elbows flexed a little and use the lifting action of your arms to raise your torso as erect as you can.   "Circularize your ampit chest" as discussed under the Tadasana section (moving your rear armpits under and upward toward your front armpits).   Lift your chest.   Have your front torso energy ascending and your rear torso energy descending.   After you have pressed your hands down to lift your chest, also rotate your upper arms outward to broaden your chest from side to side.   When you return your hands to your thighs, imagine you still have your two hands pressing down at your sides, keeping your torso just as erect.   When your hands are on your thighs, the median line of your upper inner arms should align with the median line of of the sides of your torso.
When you take your hands into Anjali Mudra (Namaskarasana, Namaste position) place them palm to palm with your thumbs and the flesh of your thenar eminences against your lower sternum and your fingers together pointing away from your chest at an angle, not pointing straight up toward the ceiling.   Press your palms together and then press them a little harder.   Feel the bones of your hands press into each other.   Take time to feel each bone press into the corresponding bone on the other side -- experience that awareness.   And then after a moment or so, relax the pressure back to the point where only the skin is touching and re-experience that awareness now a little differently.
As in all asanas, soften your face, tongue, eyes, and throat areas.   Keep them free from tension   Keep your tongue resting on your lower palate.   Have the feeling of drawing your inner ears into your head, and relaxing them downward.   When you close your eyes, note there is still a tendency for them to continue to try to look outward, to seek for information from the outside.   You must relax the eyeballs themselves as well is the muscles that move them in their sockets (extra-ocular muscles).   Your upper eyelids close downward to meet your lower eyelids.   If that seems like a silly observation, try raising your lower eyelids to your upper ones, or try having the two meet midway at the center of your eye and see how that feels.   For chanting (e.g. the invocation), relax your eyes straight back into your head.   For pranayama and meditation, turn them downward toward the floor as well.   Keep lifting through your inner body, but allow your brain and your face, both, just to melt and descend.
Keep your sense organs relaxed.   As your sense organs become quiet, your brain also becomes quieter and quieter.   Feel as though your frontal brain is receding into the back of your brain.   Allow your brain cells to recede and be quiet in that state.   Use the rhythm of your breathing to still the "lake of your mind" and draw your awareness more and more inward.