Dirt, dust, cat hair, there is all manner of filth on the stairway Lexia is on. Fortunately, slave tongue is very good at removing such filth from female feet. So Lexia takes a few steps and has the slave lick the bottom of her bare feet clean. A few more steps, and more foot lapping from the slave is demanded. Lexia finds the whole thing hysterical and laughs while the poor slave licks away all the debris from the bottom of her feet.