My 14 mo has just started this weekend behaving wiredly when unfamiliar people talk to him. We were at a christening yesterday and when my friend came up to say hello to him, ds slapped me in the face!! He kept on doing it every time someone new came to speak to him, then did it again today when we saw another friend at a farm and then some family friends at my parents' house. What is this and why is he doing it? He has never hit before. What do I do??