My 18 month old ds is frequently hitting, grabbing and scratching me and finds it really funny. I'm feeling increasingly frustrated by it. I just am not sure how best to handle it. My approach has to be consistently, firmly saying no and putting him down. I keep a calm voice and try not to give any reaction beyond that when he does it because I think pulling a pained expression or raising my voice will probably make it even funnier for him. He laughs while he does it and finds me saying 'no' funny too. If I put him down or walk away from him, he seems to think it's a game and he runs after me giggling.
Any tips? I realise it may just be a phase but it concerns me - I really don't want him doing this to other children. I know he has a couple of times at his childminders. The last couple of days it's really escalated. Help!