I'm sure I'm not the only one out there with a preschooler who has shown aggression towards her baby sister. My gut reaction when ODD hits or pushes or otherwise harasses YDD is an anger that rises up so fiercely with a desire to protect my baby that I find myself yelling or otherwise acting aggressively in return - clearly not a positive solution! All that does is escalate the problem and make our day worse, with ODD acting out even more.
Recently I read somewhere that "a child who hurts is a child that is hurting." Wow. That really hit home for me. My poor daughter is crying out for her mother's attention, and though I feel like she is constantly getting attention, she clearly needs more.
So these last few days, instead of responding with anger, I muster up every ounce of patience in my body, and I simply redirect ODD. If she hits (or tries to hit) I say, "Let's clap our hands" or "Let's go pound some clay" and if she keeps going I tell her (calmly) that I am going in the other room with the baby, and that she can join us when she's ready to play nicely. If she tries to kick the baby, I say "Cool kicking. It's not okay to kick other people, but it's fun to kick the air while we're dancing. Let's listen to music and dance!"
I realize this is nothing revolutionary, but now that I've made a conscious effort to use this technique, I have seen a HUGE difference in ODD's behavior. She still challenges me (daily!), but not as much, and because I'm able to remain calm, she is able to quickly accept the new activity, and we are able to go about our day more harmoniously. Hallelujah!
I hope this is helpful to another mama out there!