Before I explain this again in brief, I might mention that we happen to realize over the course of time that many of our old students, people who have done as many as 10 retreats with one person in particular, have never even tried to work with unpleasant physical sensations. Other people, when they attempt to work with it, it's very quick, all over. It's done in two minutes and they change the posture. I'm saying that to emphasize to you that there is work in this. A lot of old students don't do it and maybe you are one of them, so you might need to listen clearly.
In general the technique is for when you work with the awareness of the breathing. If you're doing a Reflection, and you have an unpleasant physical sensation come up, just change the posture and continue on. However, to add to that, if you have done enough practice with unpleasant physical sensations when you're doing the breath awareness, then during the Reflections when unpleasant physical sensations come up, you will not have to change your posture as often as before because you will not see it as a distraction any more.
In the beginning you just note that it is there, like any other distraction just mentally note, "sensation, sensation." Keeping it objective, it's an objective sensation. Do this as often as you can, don't get involved in the story, "Oh why me this and that," just try and note it, similar to a sound or other things. When the aversion becomes strong, not before, but when it comes strongly and it's really distracting your attention a lot, that's when you change the object of awareness. Don't just change it the minute you have an unpleasant sensation, use the noting first.
When the aversion is strong then look at the sensation's characteristics every way you can; the size, shape, location and intensity, etc. Observe it with an interested mind, don't observe it in order to get rid of it. In the technique, when I talk about it on the fourth evening of the retreat I never ever say that we are doing the technique in order to get rid of the sensation. What we are doing is changing our reaction to the sensation. It may stay, it may go away, it may get worse. But if you change your reaction, that's the key.
Observe it as much as you can, being objective with it. When the energy and concentration levels drop and the aversion is there -- with maybe some fears and worries -- change the object of attention again, focus on the aversions, worries, or the fears as they manifest in the body. Observe the body, go through it. This is much more that just a two minute thing, so keep that in mind. Observe the sensations, try to be aware of them. If your body is bent over, your hands tight, your mouth tight, whatever, observe it, note it carefully, relax it.
When the energy level observing these things gets low, your concentration weakens, the aversion strong, and everything is, "it's too much, it's too much," then practice a little bit more on patience, so it's one more minute, thirty seconds, ten breaths. It's possible during that time if you give yourself another little space, that you go even further than just ten breaths. Then if it reduces its intensity, you'll build more patience, and more determination. When you're done, and you really feel "that's enough," remind yourself you have worked as best as you can, and rather than building aversion you change your posture. There's a lot in this practice, so many of you may start work on that if you have not done so yet.