I have to put diaper on Oscar since he has a hard time holding in his poop and sometimes a little bit will "fall" out of him and I need to save my carpet and stop him from licking it off. What I do is get pee pads and cut them a little smaller into a square, then I cut two holes for his legs and a tiny hole for his tail. Then I fold the sides over like a diaper and use tape to secure it. It works really well and he got used to them really fast. They don't look perfect but they are cheap and they do the job. Good luck. Let me know what you find to work.
