I have a three year old and a two year old.
The three year old went through a phase a few months ago where she would bite the two year old out of frustration/anger. We worked on it and she doesn't do it any more.
My two year old started biting a couple of days ago and I can't figure out her trigger. She just bites out of the blue. Today she has already bitten my three year old FOUR times. The last two times I playing with them when it happened and trying to figure out WHY it is happening but I was not quick enough to stop it. There's no warning!
Each time I looked her in the eye and told her that biting HURTS and we do not bite. The third time I told her if she could not play nicely with her sister she would have to find something else to do. The last time it happened I told her again that biting hurts and we do not bite. Then I told her it was time for her nap (which it was) and put her down with her blanky and that's where she is now.
I really don't feel like I am doing enough to stop the biting but I am at a loss of what to do. If it was fighting over toys I would remove her from the situation or at least be able to be proactive in stopping the biting but as I said, it's not.
I know she understands the behavior is wrong and I know she has the vocabulary to express herself in other ways.
Advice would be very much appreciated.
TIA.

My ds went through a bad biting phase when he was two, and it lasted a long time (months and months :(). For him, the triggers were mostly: too tired, too overwhelmed (too many kids around), feeling threatened (someone else in his space or playing with his toys). So I did what I could to eliminate the triggers, but sometimes he did it while I was sitting right next to him!! He was too quick.

What I did:

- Stayed next to him constantly when he was around other kids. Constantly. As I mentioned above, he still managed to sneak a bite or two in, but this was the most important intervention I did.

- Had a clear consequence for his actions. For us, we immediately left wherever we were if he bit. No warnings, no discussions, no second chances. Of course, since it's happening at home, that makes it much more difficult. I know not everyone is a fan of time-outs, but I would tell your dd, "Biting hurts. Do not bite. Let's take a break in the other room until you calm down," and physically remove her from the actions (or toys or big sis or whatever she was previously doing). If the biting is in reaction to something (which you say sometimes it's not), I'd give her an alternative course for the next time. "Next time, instead of biting, ask your sister to please return the toy to you," or something like that. I think it's important to send a clear message every single time that it's not okay as well as giving he child an alternative response.

- We played a game called "What Would You Do" a lot. I'd set up a situation involving a known trigger. First, we'd talk about it. "T, pretend you're playing with your friend and he takes your toy away. What would you do?" We'd discuss the different options, decide on what was the best one, then act it out. The kids both loved playing this, and I think it really helped them both get some good ideas about how to react to situations. Of course, in the heat of the moment, ds would forget what he was supposed to do (and not supposed to do) and just act out.

So still, even with the actions I describe above, the biting lasted for a long time. It was SO stressful for me every time we were around other kids.

:hug I hope it's a quick phase.