I am at the gym, and I am getting really sweaty. I will make sure that when I get back home, my slave will have a lot of clean up to do. So then why bother bringing a gym towel?
At home I call my slave to me, and explain that I have just been to the gym, and went home without showering. So I order him to remove my shoes, and smell my stinky socks. I make him remove my socks, and start licking and smelling my stinky feet. He must clean them well, including between my toes.
But I have a even better treat for him! I take of my shirt, and my armpits should be really, really smelly. I used no deodorant today, and I make him smell my armpits to familiarize my stinky armpits.
I tell him to put his pathetic tongue out, and start licking and cleaning every piece of sweat from my sweaty armpits. No smell can be left behind! But he is a horny pervert! He gets a boner from licking my armpits! But when he is done cleaning, and made sure no smell is there, I just tell him to get lost!
(Real after gym worship, no shower)