Start with 2 bases standing side by side, a flier behind them, and a spotter in the back.  Have each base use their outside hand to grab a thumb to thumb grip with the flier behind them, and have the back spot bend down and grab the flier's ankles.  On count the flier will dip, the backspot will lift the flier's ankles, and the bases will snap their arms ups as the flier resists through her arms.  Once the flier is standing on the bases' inside shoulders she will stand up, the bases will support her under her toes, and the backspot will support above the knees (or ankles, or chins...whatever works best).

Now place 2 girls on either side with backspots behind each.  Have the main 2 bases and flier bend down.  (NOTE: The main flier will need to bend down at her knees and NOT with her back.)  Have the main flier grab the outside fliers' forearms with her arm on top.  The outside fliers' will have their arm underneath. The Main bases will place their outside hands on the inside waists of the fliers. 

On count the outside fliers will dip and jump, the main 2 bases will stand up, and the top flier will lean back by rolling her shoulders slightly back and standing up. (NOTE: you may want spots holding onto the outside fliers for support.  Once comfortable, they can let go.)