J.C.
Hi J.!
My baby is 2 1/2. He gets excited and likes to play and will hit his older siblings to play. He doesn't always respond when we tell him to do "gentle touches" but we've started telling him to do "tickle tickle" instead. He responds to this, I think, because he still gets to play and gets a positive reaction out whoever he's trying to play with. Sometimes a simple distraction works too. "Let's jump instead" or "hey, where is your....? I'm going to get it before you!"
Good luck.
J.