to stop me talking about whether he's done a poo in his nappy or not. 
He's 3 and we've already had one go at potty training. Now he's back in nappies and whenever he does a poo (which is completely obvious to anyone in the vicinity) I draw his attention to it (because he sure as hell isn't going to tell me of his own volition). I ask him 'DS1, did you just do a poo?' - he says:
'Don't TELL me mummy! Don't ASK me about it!' grrrrr.
Tell me this is a step forward - i.e. he's noticing his dirty nappy and feels strongly about it - and not a step back? He hates having to stop playing and have a change, which is why I think he doesn't even want to discuss the matter!