The easiest method is to go either Amsterdam's Red Light District located in the Netherlands or (in)famous brothels in Nevada USA.
Be prepared to shell out some major cash for the best sex you will ever experience.EVER!!!
Guy Two: "Great to hear it, how was she in the sack?"
Guy One: "Amazing, easily the best I ever had, it totally counts as Super Awesome Wild Monkey Sex ."
Guy Two: "Seriously? Man your a lucky SOB! Do you have her number, I want to see if she willing to have a threesome..."