Just in the last few days my ususally happy content little 8 1/2 month old son has been throwing himself back whenever I try to change his nappy or if I move him away from something he's not allowed to touch etc. Everyday he's doing it more and more, I'm not always able to catch him and he hits his head on the floor. Tonight he did it in the bath which he usually loves, I don't even know what triggered it. Does anyone have any suggestions on how to discourage this behaviour? I want to nip it in the bud before it's out of control. I'm really worried he's going to badly hurt himself.