(I promise not to bombard you with question as I already have 2 in in my first 24 hours!)
Question is, though, the bolster exercise you taught in Foundations--what exactly is that you're trying to do for the sacroliac area? Is it supposted to move the sacroliac joint some or loosen muscles? I think I remember you saying it's good to do to help the pelvis go into anteversion easier which is helping with getting into stretchlying on your side. A little confusion on the exact purpose for me now two weeks later.
Also the link you provided explaining using the bolster on the forum is broken and shows only an error page: