Help my 3yr old son has taken to smearing himself with his poo after he's gone to bed wearing a nappy. This has only recently started and seems to coincide with him moving up to the 'big room' at his nursery on his 3rd birthday. He is potty trained during the day and has been for 8months or so but still wears a nappy at night - we actually haven't tried him at night without a nappy - could this be the next step? Any other tips out there to discourage poo smearing??