Will you sleep with a robot?

Other than how I might prepare for the zombie apocalypse (fyi: I'll live up in the mountains), there is no question more intriguing to me than whether or not humans will have sex with machines. And I'm disappointed by any fictional vision of a future that includes robots, but doesn't consider the idea that all of civilization might come to a crashing halt while people are busy screwing their machines. A lot of stories are concerned with robot rights in a human world, but very few deal with humans unpacking their robot and immediately looking for the button that will get it down on all fours (unless there's a whole area of robot erotica I haven't heard about).

My theory is, the more machines do for us that people once did, the more likely it is that you will screw a machine.
If you say to your robot, "You're right. The figures for the Holmstedt account are due tomorrow. You saved my life."
You're screwing a machine.
Or if you say to your robot, "Oh, you remembered my birthday!"
You're screwing a machine.

And more importantly, the more a machine is made to appear human, with representative sex parts or even a head, the more likely it will be for people to screw a machine.

I believe that when Isaac Asimov created the Three Laws of Robotics,

A robot may not injure a human being or, through inaction, allow a human being to come to harm.
A robot must obey orders given to it by human beings, except where such orders would conflict with the First Law.
A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

he omitted the fourth and most important one:
None of the three laws can be used to persuade a robot to go down on you.