my I8 month old is at that styage where he thinks slapping, headbutting is hilarious,
and making fart noises on my boobs 
however I have noticed something rather sinister, if he doesnt get what he wants or my DP is discussing him not getting what he wants , he did a really subtle nip on his arm and looking at hime the whole time, rather scary, he can't speak yet so woulds suggest he understands more than he speaks...i digress
the slapping, he does it to me i've started putting him down if she slaps me and hes starting to get the message, but like in the park he gets really excited like hes laughing but slaps other kids in like :O
anyone else had this??