You've been a very naughty boy, step-son. You've been going through my stinky clothes again. This time, if you don't want me to tell your Dddy about this, you're going to be my foot cleaning slave. You're going to lick my sweaty feet clean. Stick out your tongue to do it now.
You're also going to suck the sweat out of my stinky, sweaty socks to get your hydration.
Now, be a good boy and finish cleaning step-mommy's feet.