Wait, so you inadvertently
threw out a whip? My advice would be to refrain from any futher hula dancing, and avoid any luaus. In all seriousness though, I'm pretty sure nobody can tell you whether or not you used fa-jing properly with just the description you gave us. For all we know you could have stood there vibrating your body around for five minutes before throwing out that whip. The "shaking" is meant to be a fast back-forward-back or back-forward-forward sort of a motion, depending on whether you are you are putting or pulling energy.
Oh, and for anyone who was wondering:Fa-Jing