He does not have to be scared of the whip or flailing arms - he has to respect them. It all depends on what your intention is when you are using your arms, or the extension - the whip.
Mine are not scared of the whip or anything normally, but when I decide I need them to move out of my way or back up I almost just have to stare at them with the right thought in my head. It depends on your energy levels. If you inside are not determined to make him back up, but more like "it would be nice if you backed now, but I won't smack you if you don't" then he won't as he can read that.