Any little thing on the end of a string makes a fine cat toy. But if you're
a perfectionist, if you demand maximized enjoyment for both you and your cat or
ferret in every play-session, then...
The problem with a simple toy-on-a-string is that you have to be cautious. A forceful jerk of the string while the cat has a claw stuck into it (or the thing on the end of it) can be painful or injurious to the cat. Consequently, you can't lose yourself in the play. You have to constantly be aware of how tightly you're holding the string, of the distance between the cat and the toy, of the cat's maximum acceleration given floor-surface conditions under each individual paw, and literally tens of thousands of other factors. Put a shock absorber between you and the cat and these monitoring chores vanish like cheese cubes at a city council meeting.(1)
What should the shock absorber be made of?
An elastic cord? Sure. But you probably don't have one. I recommend rubber bands. The very long and thin ones are best because you can loop them together like this:
If you only have thick ones you may have to cut them and tie them together. Chained in the above manner they may be too "firm". What is the best knot to use when tying rubber? I don't know.
How many rubber bands should you use?Again, I cannot answer. Three or four may suffice if your rubber bands are long and thin. If they are thick you may need seven or more. Use your judgement. Just be sure to provide enough elasticity to ensure that a worst-case scenario--a strong jerk of the string while a single claw is caught in the toy--can do no harm.
If you have no elastic cord or rubber bands you will have to cut a 1/4 inch strip off the top of your underwear's waistband. The underwear will continue to be wearable. Often there is improved comfort.
Where should the shock absorber be attached?
I recommend the following arrangement: