So, I was thinking about a way to get indeed sweaty and stinky feet - and came up with a mean way. I take plastic bags and put them over my feet - then seal them with duct gauze and put on my hiking boots. Time to go for a long walk in the forest. While I walk I feel how my feet get more and more sweaty. As I get back and take off the boots theres actually a lot of visible moist in the bags. I order the slave to get on his knees in front of me, take off the very first bag and stuff it on his nose. Hes disgusted by the stink inwards the bag - but its going to get worse for him. Next he has to smell my sweaty foot - and then slurp it! Of course its the same procedure with my other foot afterwards :-D.
