I've bound the slave to a tree in the woods - and then make him lick my dirty boots! He has to clean the dirt-covered boot soles with his tongue - and of course they're extremely dirty after wandering around in the woods. I watch him closely as his tongue gets more and more dirty - while my boots get cleaner. In the end I couldn't resist to rub my boots in the dirt again - and then make him lick them AGAIN :-D