I believe they have them in baby departments of stores. It's a little windy
gadget. I keep meaning to get one (same situation) but forget, although, my
cord chewer passed away this year so it isn't as big a priority.

Do you know how to make a rigger's gasket?  Hank the cord around your
hand and make the last loop triple-length (or more, for decorative
purposes).  That you wrap around the mid-point of the hank and pass
the tip (which will be a loop) through the hank on one side of the
wrap.  Hook that loop on a picture hanger.  It looks spiffy if you get
it right, with the plastic tip of the cord on the inside of the hank
at the bottom.  There is also a double-ended slip knot that looks
good.  Pick up a knot book, it's more fun than a gadget.

Charlie

Spray the cords with bitter apple.  That should keep him from chewing on
them.

Celeste