DS has always been quite rough with grabbing at us. However, I feel that he's old enough now that it's not accidental any more and most of the time seems to be aimed at DD (who's 3). Pulling her hair or grabbing her face. We can't seem to figure out any pattern to it and also not sure how to respond. At the moment we tell him no and move him away but he just laughs
and then heads straight back over, often to do it again.