i had to create safe places where i could leave DS and DD couldn't get to him. there were 2 rooms that dd (at that time) couldn't open the doors, our bedroom and the bathroom, and i would 'hide' ds in there if i couldn't be right there. At the same time, we were encouraging 'gentle hands', and talking about how ds liked when dd held his hand or rubbed his foot. Also by creating times when dd could hold ds, she got bored with it (for a little while).

good luck.