He has been potty trained for somthing probably approaching 6 months. We recently got rid of the potty and he has been using the big toilet for around a month. Just in the past week however he has started sliding on and off the toilet, for no apparent reason creating a huge mess. Last night he managed to smear poo over all his clothes his night time nappy, the floor the toilet on his hands the stairs his legs and of course his bottom. He also did it in the morning and was told not to. He has now done it again and I'm afraid I have lost my temper with him. He is not stupid and I am fairly certain it is mostly intentional. what else can I do to stop him?