For those of you who have already had a second baby, how is your toddler behaving around the new LO?

We just brought home our newborn and he loves her and is curious about her; but I think we messed it up ☹️ we were very tense about him being gentle with her, and now he keeps being nice and loving towards her but suddenly gets rough and tries to hit her, and we react very strongly so it has become a game for him 🙁 it’s terrible. I think we messed it up and now I can never keep him around her because he wants to get a rise out of us and tries to mess with her.

How did you guys handle it? Any advice on how I can fix this situation? I’m quite upset about this.