Donkey mouths are very tactile, and very luscious lips encase those teeth which for the most part are quite benign. We have a natural reluctance to put our fingers in there but when we are relaxed we do. If we have a visitor, for example we might be chattering away with them, and the Donkeys will be fascinated and come and stand by us. A gentle nudge will be followed by a mouthing and as we are concentrating on the conversation, we are not conscious of our fingers playing with their lips – and they love it!