Slave Has To Lick Our Muddy Boots

Were taking the slave for a walk in the woods. It rained quite a lot in the past days and the ground is very muddy - quickly our boots are covered in mud. We sit down on a fallen tree and show the slave our dirty boots, but he hesitates - doesnt he know what his job is?! We make him lick all 4 muddy boots clean and in the end his tongue is the only thing left dirty!