Biting...?

Ok so DD2 who is 2.5 has suddenly developed a nasty biting habit...directed only at her sister.

Started one day when DD2 was smooshing her face on DD1's leg and DD1 started shrieking and carrying on about DD2 "trying to bite me". Well, you couldn't buy an incentive like that could you?

It has predictably since developed into full-blown biting.

HOw have other people managed biting?

ETA DD1 is nearly 12 and should know better. I have spoken with her about her inflammatory behaviour and the need to move away - FAST - when she sees the choppers about to come out.

My parents said i was a biter and apperently they bit me back. I know it sounds nasty and im not saying do it but i never did it again.