Here's what you need.
One pair of clean (you'll see why next) track pant you no longer want.
Here's what you do with it.
1. tie a knot, nice and tight on the end of the leg.
2. cut off the extra. (you weren't expecting rocket science, were you???)
You're almost done.
Loading the toy. (this is the fun part).
Show it to your dog, then look at the toy, really look at the toy like it's the most fun thing ever. Look at the dog, sidewise even better, look at the toy. Open wide and CHOMP the toy (remember, I said CLEAN pants), Yum, bite hard, look at the dog. The dog should be looking mighty curious by now.
Chomp again, yum! Give it a shake, yum! Tease your dog, and chomp & shake again.
And, when you're dog is really ready, (Sonic by this time had eyes big as saucers, and had is mouth open in an 'I want that, and I want to BITE IT' expression).
Toss the toy.
You're done, now you can make another. (oh, and make sure your socks are in the drawer. If you use a toy like this, socks are fair game)
Lower image shows a WIP in the Moleskine, using pen, will add colour another day, with my menagerie as the subject. And a finished full colour work on Stonepaper (lower).