I notice my office boots are quite dirty and I want the slave to clean them - but I will make it a little harder for him! I step on his naked chest and then order him to lick the dirty shoe soles while I trample him. Of course, with me standing on him the whole time he needs longer to clean the boots than usual. When they're finally clean I take them off and continue to trample him under my sweaty socks - and of course he gets to sniff them as well. When he whines too much I take off my socks as well, stuff them into his mouth and trample him with my bare feet for a while!