You need 6 people (3 fliers and 3 bases)

Start with a shoulder sit in the middle and toss hands on both sides of the shoulder sit facing opposite ways.  On count the fliers in hands go up to liberty hitches as they hitch to the shoulder sit flier in the middle.  Make sure that the fliers on the outside keep all of their weight on the supporting leg.  The hitching leg is just and effect.  The top fliers need to lean forward to initiate the movement, then lean slightly back to stop the rotation.  Try turning 180° to give the crowd a good visual.