I had 8 ferrets before and they were fun. Miss having them around. Not sure if the treat (inside the "toothpaste") is right or harmful for ferrets. Check it out in store before you bid/win. Happy Bidding!
One word: Licking...It is a good challenge for some cats to do it. If they can't (or not intersted), just spread the paste around it and put treats inside. You gotta be creative.