I'm just starting to sit my little boy on the potty, at 13 months. He sits on it OK in clothes, but if I put him on it naked he cries. I think it might be because he is uncomfortable since there were red marks on his legs when I took him off. Can anyone recommend a small potty that is suitable for boys of around this age, as I think that the ones I have (Tesco!) might be more suited to 2+ year olds?