We experimented with a number of heights and angles. Liz attempted fighting the appliance but it was at all times harder. Trying to pull back against the appliance turned out to be quite unwise because the mechanism pulls back faster on the next stroke. Liz drooled all over the location of course, and girl had a lot of diversion! When I unlocked her hands to let her out, maid decided doll wanted another go and tried to reach the controls herself to receive deepthroated some more!!