This technique is used to help relax the muscles in the pelvic area so that they can come into better alignment on their own.  The hip bones can come out of alignment through normal daily functions like sitting, lying and walking.  We have unconscious muscle patterns that together create our posture and movement patterns.  If these patterns have imperfections in them, over time our body will actually distort our upright posture in order to keep our head level with the horizon.  These postural distortions can occur in the pelvic region by having a high and/or a low hip bone.  SOT blocking is a great way of helping these bones to come back into proper alignment.