DIY making a button down , fitted, for Hour glass figured Ladies

supplies

 1. elastic
2 thread
3 hand sewing needle
4 button
5 scissors
6 patients and time

left, before                                  right, after

the elastic does show in the back

sew the button onto the elastic

with the shirt on, attach the elastic button to the shirt via the button hole closest to your natural waist

then wrap the elastic behind you and stretch it to a comfortable tightness, and see where you need to make the button hole in the elastic for the other end. 

this is the finished product. I made the button hole in the elastic by making a scissor cut in the elastic and using thread I whipped stitched the edges, and secured the ends of the hole. Almost the same as mending a hole in a sock