When DS was first born and pretty much until the time when he could sit up, DD was always really good with him. Very gentle, always bringing him toys and trying to make him smile. For about the last month or so she has started to rough house with him. I think some of it is a sincere desire to play with him. Last weekend her cousins were in town and they always rough house and since they have been gone it seems like it's gotten a little worse. I think the majority of it is just testing the limits, like how far can I push this? Part of the problem is DS is the most easy-going kid alive, I swear. She can do almost anything to him and he will find it funny or at the very least not complain, I don't think she has ever made him cry with her antics. I care for another little boy DS's age who is much more sensitive and cries if DD tries to do any of this with him. So she seems to leave him out of it more or less, or won't push it so far with him. But here's an example, today I was going to change the diaper of the boy I care for. I put DS in the excersaucer even though I know he prefers the floor because quite honestly I don't trust DD. She asked me to leave him on the floor, so I said, "OK, only if you are going to play gentle." She agreed. I change the diaper (just a room away but I can't see them) and come back to her sitting on DS's stomach. I tell her to get off, that could hurt him, I don't sit on her, etc. She does, but then lays down next to him and starts rolling back and forth swinging her legs so they are landing on DS. I tell her to stop. She does, then starts grabbing him by his chin roughly. At this point I pick her up put her behind the gate for a few minutes then return and we sit on the chair and talk about what happened. I'm mad at myself because I yelled, "I'm so sick of this!" as I was bringing her behind the gate. I'm just not a yeller and don't want to become one.
We only use time-outs if she gets physical with someone. About a year ago she went through a phase where she was hitting/pushing us out of anger and it was an immediate time-out, no warnings. This approach was really effective and it's extremely rare that she does this now. So should I just start putting her behind the gate for anything that's too rough and hopefully she will start to tone it down? I've have tried giving her ideas on how to play with the babies in a nice way, reading a book, giving them toys, playing peek-a-boo and of course none of that interests her. I try to get us outside every day, we go for a walk, play at the park, go to story-time when they have it at the library, she rides her bike, to try to and make sure she's not cooped up with the babies all day. Any other ideas?
I just really want to nip this quick before it becomes a habit, plus I'm obviously worried she is really going to hurt one of the babies. A few other pieces of information, it seems to be worse when she is tired. This particular incident happened before nap, though that's not always the case. She has had a lot of big changes in the last 4 1/2 months, potty trained, big girl bed, the baby who stays with us during the day, sitting in a big chair to eat.