Yuki grinned at the girl's begging, shaking her head.  "No... I wanted some entertainment for tonight, and you're going to provide it for me.  If you do as I say, and don't scream or put up a fight, I'll let you go tonight, and give you a large tip to make up for it.  But if you refuse, or do anything else to inconvenience me... well, I'm sure I can find a few uses for a new sex slave, hm?"  She waited a bit to see the girl's reaction before continuing.  "Now Lisa, the first rule is that you aren't allowed to orgasm without my permission.  If you do, you'll be punished.  Let's see... how about we start with you showing me how good that tongue of yours is.  Lick me to an orgasm," she ordered as she sat on the floor in front of her, lifting the bottom half of her outfit to bare her pussy to the girl.