Ideally I'd like to find a couple of girls interested in playing this one out.
A guy and two girls, friends for a few years, college age or thereabouts. They've flirted, joked, teased, but never gone further than that. He invites the two of them out for dinner, his treat, since he says he's had a bit of luck and wants to celebrate. After dinner, he lets them know about his lottery jackpot, and makes them an offer. He'll give them each a quarter million in return for their agreeing to become his slaves for a period of time, and obeying his every wish.