DH and I are very sick and tired of DS's hitting, headbutting, etc. We remove him from the situation (baby timeout) talk to him (short words) keep telling him no, even ignored him for 5 minutes or so - trying to send the message if you do that/act like that nobody is going to play with you. I feel bad for DD, DS will pull her hair or hit her in certain situations. She is a trooper a bit though and tells us and tells her little brother - NO! It's been going on for about close to 2 months and we are at wits end - ugh!
Re: When will it stop...
If DH or I are holding her and she hits- we set her down immediately and walk away. If we are playing on the floor with her and she hits, we get up and walk away. If she follows and continues she goes in the PNP (no toys) for 20-40 seconds.
the PNP has become time out and she doesn't like it at all. usually the threat of time out stops her in her tracks (when he is grabbing the blinds or dogs tail)
but consistency is key. whatever you decide to do, make sure you and DH are doing it and eventually LO will stop.