manequins

duct tape

take waist measurement to reference later
wear a big tshirt, with extra fabric (another tshirt sleeve?) basted onto/around neck
using lengths of duct tape about 1' wrap body and cover with 3 layers total
make sure neck and shoulders are covered (enough for capped sleeves) and posture is correct
mark with permanent marker where the natural waist is 
measure from floor and mark horizontal lines around hip, under bust, wherever you want level lines
mark plumb lines up center front and back 
measure from floor an even distance all the way around and mark for a level hem
cut down center back, take off
use more duct tape to close back, cut off sleeves, neck and hem
close up arm and neck holes (with duct tape)
stuff with batting, and close up bottom with more duct tape