dd2 (20ms) has started hitting her sister; mainly as a way of trying to play I think, she is quite happy and has no malice, though sometimes she does it to get a toy off her
dd1 however is disabled so can't get out of the way and ends up in tears after being beaten up by a grinning toddler
dd2 is just a bit highspirited and not super-gentle - she often whacks me while bfding just as an idle thing to do
so I don't want to come on all heavy since she's lovely & affectionate and a very happy and well behaved child but I do want her to know that that's not acceptable
suggestions pls