my 2 year old daughter does the same thing, from when she was crawling we put the potty in the front froom so she got used to it, she now says she needs a wee or a poo so she goes and gets the potty and we take of her nappy and leave her to her own devices sometimes she will do a little somthing or sometimes she will panick and ask for her nappy on then do it in her nappy, my midwife says they will let you know when there ready so maybe this is the strart of him telling you. if they see you on the toilet it is ment to help them understand what it is for and not be scared of what is to come,
