When I came to Europe in 1995 I remember they had these special knickers in Italy and the slogan for them was "Culo basso bye-bye" which roughly translates as no more dropped arse. They were made of that special fabric that sucks you in but they also had 2 little padded bits at the top of your bum where I guess you cheeks would be if you had a pert bum.
It seems that women are still a sucker for the knicker quick fix. This time the undies are called magic knickers and the fabric is impregnated with all sorts of fat blasting substances that wick away the fat in just a few weeks. Meaning that you have to wear the knickers for that long I guess and if you washed them wouldn't all those special substances go away. Euuuugh!