You take an old pillow case or make them. I make different sizes, you just take different size scraps I like them small as they fluff better. I put scraps of thread and material and just keep adding until it's full. My lil dog tries it to see if it's ok. Lol. Then sew shut you can make a cover for it and it's all washable. One paddy here says she also uses dryers sheets and dryer lint in hers!
Goog luck let me' know how it goes!