We go weak when a fingertip brushes our nipples, and melt when those fingers trail below our briefs. But after a while, the same old foreplay starts to feel a little routine. Want to bust out of that sexual rut? Here's our guide to the body’s most underrated erogenous zones.

Erog-a What?

The ancient Greeks must have been romantics; they gave us the word "erogenous." "Ero" is derived from Eros, the Greek god of erotic love, while "genous" means to produce or generate. Put them together and you get "erogenous," the generation of erotic love.

Erogenous zones are the areas of the body that are most responsive to sensual touch. The body has primary erogenous zones, where our nerve endings are concentrated. These include the clitoris and the head of the penis. It also has secondary erogenous zones, which have erotic significance due to sexual conditioning. For example, if an old lover always touched the small of your back when you kissed passionately, this may become an erogenous zone for you.

Fun with Feet

Playing with feet isn’t just for those of us with a fetish. The toes and feet are incredibly sensitive, and touching them can elicit a powerful response. A large area of the brain receives sensations from the feet and toes, so paying attention to them can be very stimulating!

The ancient art of reflexology found certain pressure points in the feet can trigger sexual arousal. It won’t work for everyone, but a soothing foot massage is a great way to find those hot buttons!

A Beautiful Back

Consider the back one long erogenous zone. Trace your fingers down your partner's spine or leave a trail of soft kisses, making sure to linger at any points that make your lover gasp or moan. The small of the back is particularly rich in nerve endings.

Treating your partner to a back massage after a long day at work is another great way to get things started. It doesn’t just release tension, it also increases blood flow to the pelvic region. Ooh la la! (Learn more about the importance of touch in 10 Things You Didn't Know About Foreplay.)

The Sensual Stomach

Forget those body hang-ups and enjoy how good it feels when your partner touches your tummy. The abdomen is such an erogenous zone that some women can even orgasm just through flexing the muscles! Even if you can’t achieve that, sensual touch and massage can do wonders, and send delicious tingles down your body. (Body image can really get in the way of great sex. Get some tips on how to get down with the body you've got in Worried About Weight? How to Have Spectacular Sex Anyway.)

Love the Butt

A firm hand on the buttocks can feel delicious. Grab handfuls when you’re kissing, or spank them if you’re feeling brave. Not everyone warms to this kind of sensual punishment, but it can drive the right person crazy.

Others prefer a lighter touch. Whichever you choose, spend time celebrating this area. If you feel self conscious, try to focus on how you feel, rather than worrying about how you think you might look. Lower inhibitions lead to amazing sex. (And your partner chose you ... and your butt!)

The Sexy Side of Knees and Elbows

The knees and elbows aren’t the most attractive body parts, but you can discover their sensual sides with a bit of exploring. There are many nerve endings concentrated in the underside of these areas just waiting for you to take advantage of them.

These sweet spots can get ticklish, but they can also feel amazing if you kiss them or massage them gently with a little oil or lotion. If you get a good reaction, don’t be afraid to take a little nibble!

That Sexy Space Between the Ears

We can’t stress this enough: Don’t forget the brain. Research suggests that the brain is really our biggest erogenous zone. After all, that's where sexual desire starts. It's also the area that commands our orgasms.

Now, of course, you can’t stroke the mind the same way you can the other erogenous zones we’ve mentioned, but you can stimulate it. Make lovemaking a visual feast with mood lighting and plenty of eye contact. Breathe in pheromones, and wear your partner’s favorite perfume or cologne. And remember to communicate, whether it’s whispering sweet nothings or talking dirty. Better yet, get those neurons firing before you even touch by sending your partner a sexy note during the day.

Sex Is Sensation

Sex is all about sensation, but what we often forget is that our bodies have a whole landscape of sexually responsive areas. Of course, everone's sweet spots are a bit different, which means it'll take some time to explore and map out what works for you and your partner. Chances are you'll both enjoy the effort so much, you won't even mind.