James has hit the "No. I don't want to." stage. So after we ask him to do something (you know, really horrible tasks, such as getting dressed, or finding a toy!) and get this response, I usually follow up with, "It would be very helpful if you could....., please." And he usually obliges.
Yesterday morning, after being up to both James and Eleanor the night before, he came round to me in bed far too early, and told me, "I've done a poo. Can you change my nappy?" My response was rubbing bleary eyes and asking him why he didn't do it in the toilet...
"Mummy, it would be very helpful if you could change my nappy now, please?"
So I did!