We didn't have this one. But it sounds like this is a good one for a replacement behavior. The best replacement behaviors is one that not only replaces the hair twirling but also makes it impossible for her to do both the replacement behavior and the hair twirling at the same time. Ie. her hands are busy. You will have to put some thought into this. But for example, suppose you decided that you were going to use pressing her hands together to replace hair twirling. You would practice that behavior in the absence of hair twirling just so she could learn it. Then reinforce her with something she likes when she is doing that successfully. Once she can do that, continue to practice it throughout the day (in short spurts), but also have her practice it immediately when she starts or looks like she is about to start hair twirling. Then reinforce. If you ever she her do hand pressing all on her own (initation), then reinforce really big.

I would also consider a replacement behaviour from the other side of the coin. Our scalp is extremely sensitive and could the hair twirling be providing some sensory input to her scalp? Do other activities involving the scalp tend to trigger a good or not-so-good reaction, for example: hair brushing or washing the hair. I have tried to massage my son's scalp as brushing, combing, washing or cutting hair has always led to trauma. He only got over his aversion to wearing a hat / helmet because he had to in order to ride the horse, which he loves doing. (Use their passion to motivate them.) Once the child has learnt a replacement behaviour, they can use this independently to help regulate their focus and attention.

Just an FYI :) She may have what's called "trichotillomania"- which is a hair pulling disorder. Jill's advise is great for this behavior regardless of the formal condition.

My son found his cousins toy and loved it. It was a little figure that bends and fits in your hand. It's not noticeable but it works especially in public for him to play with. And also depending where we are I will usually start massaging his hands with medium pressure. Before this he would fidget with his hands, bite his hands, usually end up breaking something because he would just dig with his nails on whatever he could and be sneaky about it.

Wonderful question and tips. My twins pull out their hair including eyebrows and eye lashes. It drives me crazy.....