Liz Rainbow brings her slave in to be put to work.   She has him smell her socks to show just how hard she has been working.
Well, there's going to be a lot of sweat under there.
She smears her socks against his face, "you're going to be smelling of my feet all day now," she tells him, before having him remove the socks.
Under her instruction he must clean the sweat from her feet.  From kissing, licking, sucking.  She has him old out his tongue while she rubs her feet against them.
 
While he is cleaning the sweat she adds some verbal, that, perhaps she can have a party with other guys, and he can use that mouth and tongue to become a cum cleaner!    But right now, he is at work as her sweat cleaner.
In her style, she is delightful and playful as she gags and taunts the sub with her small, soft (and somewhat sweaty) soles.