You need 8 people (3 fliers and 5 bases).

Start with a shoulder sit in the middle (walk up or toss) and a walk up thigh stand on both sides facing inward.  Make sure that al 3 start close together so that there is No/little movement when putting up this pyramid.  Also remember to have spots behind for safety issues, and spots help with the lift with hands on spotting at all times.  On count step and lock together for a clean effect.  As the fliers are stable, have the fliers of the outside thigh stands hitch their feet to the thigh of the shoulder sit.  Once complete, everyone hit Hi-Vs for the finish.

Note:  You should put and elevator/shoulder stand behind this pyramid for an added effect.