This is what such a conversation might run like:

Man: You want to have sex with me?
Woman: Oh no, please!
Man: C'mon! 5 minutes...

Probably you should consider sex less as something you can ask for, and more as something you can earn yourself. I have slept with men who I got to know the very same evening, maybe four or five hours earlier, but that never happened because one of them asked me to have sex with them. It was because there was a sexual spark flying, and because I wanted it. If I hadn't wanted it, I wouldn't have had sex with them, end of the story.

And as I rumble along, please don't think there's such a thing as free sex. You either pay for it (prostitution), or have to carry my suitcase, or you have to do some work around my apt. that I haven't done so far. But sex for free? Not here