The imagination is a powerful tool when it comes to spicing up your sex life. And who better to imagine than a super-hot celebrity?

Some will argue that you should focus solely on your lover while making love. But fantasy, used sparingly and on the down low, never hurt anybody. In fact, your lover may be pleasantly surprised at how “into” the sexual encounter you are.

So ... who makes you drool? It seems everyone has a dream boy or girl they'd love to get with if they could ever be so lucky.

Truth be told, I’m not into the Hollywood scene. I don’t know who half the people are these days who are “famous” – or trying to be. Maybe it’s the Icelander in me (people like Jerry Seinfeld and Kevin Costner are known to vacation in Reykjavík since people leave them alone), but I could care less about who is supposed to be a big deal.

But many people find the rich and famous to be a huge turn-on, and I’m a proponent of using what works for you.

To some, there are too many good reasons for ogling the world’s sexiest. They:

— Give us a concrete figure for our sexual imagination.

— Act as a form of foreplay, revving up our libido.

— Allow for escape from our reality, including any difficulties in our own relationships.

— Provide us with an example of what to strive for in becoming sex symbols ourselves.

— Give us somebody to fantasize about during sex, ultimately helping us to maintain long-term, monogamous relationships.

Since it’s not my thing, I asked some friends to weigh in on who gets their libido revved up.

In a world where Brad Pitt, George Clooney, Angelina Jolie, and Jennifer Aniston always rank tops, their answers may not be what you’re expecting ...

"I have loved (Cuban model) Mayra Veronica for years. What a body. And she barely speaks a word of English, which somehow makes her even sexier,” said one friend.

“For me, the sexiest man is Robert Pattinson — his mesmerizing blue eyes, gorgeous hair, perfect lips... Goodness gracious, I just melt! But, I also love his humility/modesty. His instant success from the Twilight Saga has not gone to his head in any way. He is so funny and I find him even more appealing by the fact that he doesn't ‘get’ why people call him sexy. Also, he is not afraid to show his sensitive side. At the New Moon premiere, he got choked up, on camera, by one fan's story of how New Moon changed her life. I could go on for hours about why I find him so sexy and incredible, but I'll just leave it at that,” another said.

Some others said:

“The sexiest woman is Megan Fox. I can't pinpoint what exactly about her, though.”

“British actress Samantha Morton, for the soft innocence she exudes. My obvious choice would have been Burlesque maven Dita Von Teese, because of her craft. She walks a fine line of art and porn. Lady Gaga too. She's sexy, talented and freaky all in one.”

“I go for natural looking women. Case in point: Pam Anderson is much better looking when her face isn’t caked with make up. But my fav is Jennifer Garner – she’s breathtaking, especially with all of the looks she had in Alias, but so girl next door.”

"Christian Bale is the sexiest man! He is such an intense actor. He has an incredible body. And I love the accent!!”

“Gabrielle Anwar is sexiest because she seems incredibly classy, yet still amazingly sexy and at 39 she still looks 25. Then there’s (German actress) Alexandra Maria Lara for her beauty on and off the screen, and Natascha McElhone because of her gorgeous eyes, then Stacy Dash because she is flat out exotic... and Catherine Bell, because she is smoking hot...always...although 15 years older than me....I'm still in love, lol!”

"I agree with People mag - Johnny Depp is my boy!"

Molly Crabapple is sexiest for being cute and talented and creating Dr. Sketchy, which is the sexiest thing ever.”

“My favorite men are Dennis Haysbert, Jay-Z, and Jamie Foxx. They are all extremely talented, have great voices and nice bodies, and dress well — not to mention the fact that I love dark skin. My favorite lady is Liv Tyler. With her it's all about the lips and her curvy figure. She's a true classic beauty.”

What makes this list endearing are the reasons given for the sex appeal. Sure, in some cases, being eye candy is the primary reason, and rightfully so in many being absolutely stunning.

At the same time, the “why” of somebody being sexy speaks volumes — their mannerisms, personality, sensuality, energy, and goodness. This are what get a person’s heart rate going — which is why I’ll often have people confess that the world’s sexiest person is ultimately their partner.

Dr. Yvonne K. Fulbright is a sex educator, relationship expert, columnist and founder of Sexuality Source Inc. She is the author of several books including, "Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots."

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