I used to have a problem with Corkscrew pooping in the bathtub. After I learned he was healthy I did a few things to get him to stop. I made sure to clean the litterbox more often, I sometimes would get lazy and wouldn't clean it everyday so now I make sure I clean it everyday. I also gave him more attention and started giving him treats out of my hand on a daily basis. Then wondering if the tub was just an attractive place, I would leave it filled with a little water to stop him from going in there. Now he doesn't do it anymore unless I go away on a trip.