My suggestion is to train your ferret to come to a squeaky toy when you want
it to make an appearance.
 
First, a squeak toy is easier heard through the inside of furniture and
outdoors if an escape happens, second - ferrets don't understand words, but
do react to noises.
 
Squeak the toy - reward promptly with favorite treat.
 
You can also teach your ferret to roll over by showing the ferret a cat
treat or raisin in your hand, then make a fist and twist your hand - at the
same time, push the ferret's butt over with your free hand to get the ferret
to lay down.  Then using the hand with the treat, move it over the ferret's
body/head until the ferret rolls over.  After awhile the ferret will
associate the treat with the hand movement with roll over.
 
Pam Grant (who has a ferret that rolls over and one that wags his tail)
[Posted in FML issue 1428]