I just reviewed my notes from Leigh's talk during the retreat about the body scan:
We start at the top of the head. Our job is to just notice the sensations that arise in various parts of the body as they are being scanned. Those include body sensations, and sometimes also emotional sensations that may be buried in the body. In some parts, we may not notice anything. We are mostly staying on the surface, and we go top down, and right left. When switching from one arm to the other, we put the attention out into the room and then back onto the other arm. Same with the legs. This order can be changed to fit one's preference. The sweeping just has to be systematic and cover the whole body.
It is not unusual to get nauseated the first time one does the body scan. It is actually a good sign that toxicity is being released from the body. It may happen once again at the most.
35 to 45 minutes is optimal.
The body scan is a good practice when feeling agitated or sleepy, or when one is feeling least inclined to practice. Also, if one doesn't like the body scan, it is usually because of a lack of being in touch with the body, and of not picking up sensations.Body scan, loving kindness, two great practices when the mind is dull, or not settled enough for 'just sitting' . . . One really has no excuses for not doing formal practice.