K.G.
I have this trouble all the time. What I do is to take the elastic completely out. Then at one end of the elastic attach a safety pin to it (a large one). This way it is easy to feed through the waist band , by pushing it through and gathering some material. Then hold on to the safety pin while pulling the material tight. Then do the same all the way around the band till you come out the other end. I hope this makes sense.