My 18 month old son has started slapping (gently) my face, he has started to do it to the other children at childcare too. Im horrified that he's doing this as he's usually so gentle and loving. When he slaps me i take both of hands and say 'No, you dont hurt mummy, that hurt mummy' Is this the right thing to say? is it just a stage he's going through? Any other advice on how i can stop this behaviour?