My just 3 y/o daughter is very rough with her new infant brother (2 1/2 mo.) She hugs, kisses and squeezes him very hard, she taps his body hard, squeezes his arms and hands.  Most attempts at play with him are rough. At times, this appears very intentional (attention-getting, jealousy).  Usually, though, it seems to be out of her attempt to love and cuddle with him.  She says, "He's so cute!" and then squeezes him excessively.  My husband and I are continually instructing her and roleplaying how to GENTLY play with him.  We try to involve her in his life in different ways as "Mommy's helper". We praise her soft, gentle behavior and discipline her immediately when it is obvious she is being aggressive with him. We've been using the Command 1-2-3 method with an adult-size chair "time out"(with timer)for three minutes (is that an appropriate timeframe?)when she doesn't obey. The behaviors do not seem to be decreasing and I find myself telling her to not touch or get near the baby at all, which saddens both me and her.  What are we missing?  How can we diminish these behaviors?  She is an emotional, dramatic child, prone to yelling and crying tantrums when not getting her way, occasionally slapping my husband or me when not getting her way.  These behaviors immediately land her in the three minute timeout chair.  On a side note, how do you reinforce disciplining these types of behavior when out in public and your timeout chair and timer are at home?