Placement of the block under your sacrum should be such that the sacrum feels planted firmly and contact across the back of the pelvis made evenly. This is a matter of where the block is in relation to the sacrum, coccyx and low back --- it is a placement, and not a muscular effort. The sacrum should be given first priority for placement on top of the block. The block should not be so low that most of the support is offered to the coccyx and only a little into the sacrum.

