On sitting the lotus, here are some instructions I find very useful, every day almost:
An empty hand grasps the hoe handle
Walking along, I ride the ox
The ox crosses the wooden bridge
The bridge is flowing, the water is still.
(“Zen’s Chinese Heritage”, Andy Ferguson, pg 2, copyright 2002 Andrew Ferguson)
So he abides fully conscious of what is behind and what is in front.
As (he is conscious of what is) in front, so behind: as behind, so in front;
as below, so above: as above, so below:
as by day, so by night: as by night, so by day.
Thus with wits alert, with wits unhampered, he cultivates his mind to brilliancy.
(Sanyutta-Nikaya, text V 263, Pali Text Society volume 5 pg 235, copyright Pali Text Society)
In my understanding the hoe handle is the sacrum. The empty hand works as Gautama described it, “as in front, so behind: as behind, so in front”; if I am conscious of activity in the lower abdominals, I look for consciousness of activity at the sacrum. The Gautamid described the feeling of the first meditative state as like gathering soap powder that been sprinkled around the inside of a cauldron into a ball, until the ball doesn’t ooze; if I look to the state of mind I have waking up or falling asleep, and I am conscious in front as behind, behind as in front, then I can allow consciousness to fall where it may and observe activity initiated by the stretch of ligaments. I have to be waking up or falling asleep to observe activity initiated by the stretch of ligaments without startling myself and interrupting the reciprocity and balance of the action, and I have to accept what I feel into my sense of location, but this is no big deal; the effort is being where I am as I am where I am, to wake up or fall asleep.
I usually stretch my legs, first one and then the other, before I sit. I grab my toes or as close as I can get, and wait until I have the feeling to touch my head to my knee or whatever feels satisfactory. This usually requires specifically waiting for feeling for motion at the sacrum; the sacrum in my experience is constantly rotating forward and backward, and on other pivots as well. Yet, as behind, so before.