dd has developmental delay and is probably about a year behind her actual age."Terrible twos" are kicking in.She is almost non-verbal so obviously getting quite frustrated.When she tantrums she is completely undistractable.How best to deal?If she is sitting on my lap she throws herself backward and "headbuts" repeatedly.At the moment I am ignoring the worst and signing/saying no firmly,to very little avail.Any sensible behaviour modification solutions?Thanks.