I've recently discovered the best way to give a guy a good
quick backrub.
As one of my test-subjects put it, "it makes me want to melt in your hands... and become your sex slave."
It's more of back scratch than a back rub, really, but it definitely makes for a good segue into a full-fledged rub. It also works nicely if you simply feel the need to assert complete power over a guy at any given moment.
Don't try this if you have long nails.
Start just below the guy's shoulderblades. Rub lightly with the tips of your fingers in a circular motion. Slowly begin rubbing harder as you move your fingers all over his back, continuing the circular motion. If your guy gets really into it (you can tell if a look of euphoria flashes across his face, while he moans slightly), you might also try gently massaging his neck- still using your fingertips, rub in small circles from the base of his neck to his hairline, and back again.
An added bonus: your hands don't get tired the same way they do when you get a traditional massage.