Start with and elevator and have a base in front.  Have the flier and the base in front grab a thumb to thumb grip. 

On count, have the bases dip, slightly toss, guide the flier up to a handstand, and adjust their hands to the thigh/waist of the flier.  The flier will ride her hips up, and push herself up to a handstand.  The base in front will keep your hands at shoulder height, and remain sturdy for the flier.