So I use to think that my daughter was just learning her motor skills when she would pinch, bite, pull hair, hit... but she does it on purpose. She uses all her strength to pinch or bite or hit. She like shakes and grunts bc she's using so much force.

It actually hurts and she's only 9months. When I tell her no she just smiles and does it again. I've tried being stern with her and when her dad tells her know she does a little sad face and continues doing it.

She's just so rough and I really don't know how I'm suppose to "punish" or get on to a 9month old. I can't put her in time out, i dont want to spank her she's too little, and when I tell her no she just doesn't listen.

I really need some advice because I don't know why she is so aggressive and how I can teach her that she can't do that.