When Otis broke his leg he stopped covering up his pee because it was just to hard for him to do. Now that he's all healed he still doesn't cover it up! This causes major problems because my other 2 cats step in it from time to time. When he goes #2 he covers some of it up but doesn't do a very good job. I've tried to take his paw and cover it but he still doesn't get the point. Any advice?