For males, in short, there is no guaranteed way.
Here is how people fuck:
They date. For men, this requires quite a bit of money. Basically, you buy sex with a few drinks, a few dinners, a few movies, and some bullshit conversation.
They use hookers. This is like dating, except more direct. You leave money, usually on a table by the door, and lay down on the table. You can let them massage you, or just turn over and ask for sex flat out. If you payed right, you'll get it.
They use craigslists hook up section. This doesn't work for dudes.