But after we’d been buddies for about four months, one day when I tried to make an appointment for sex I was rewarded with an e-mail—or, rather, a she-mail—in which he resigned from buddydom. He wrote that sex was "sacred" and should be reserved for people who are in love rather than two friends "who happen to be physically attracted to each other and sleep together when they’re horny." He said he’d "hated" being a fuck buddy.

I immediately took inventory to see if I’d broken any of the rules that come with being a buddy: Had I become needy? Did I ask him not to see other people? Did I ask him out on a date? No, no and hells, no. This was strictly a sublet-with-no-option-to- take-over-the-lease situation. So what had gone wrong? What kind of a guy turns down regular duty-free sex, and with me, no less (if you could see me, you’d understand). It occurred to me that maybe I was just terrible in bed, but I quickly suppressed that thought. And to preserve my enormous ego, I decided that this must be happening to everyone else.

Indeed, a few months ago, when The Onion gave us the faux headline, "Fuck Buddy Becomes Fuck Fiancé," it raised a valid question: Where have all the fuckers gone?

Have they all gotten married?

I called Kyle Smith, author of Love Monkey, part of the fledgling "lad-lit" genre. "Fuck buddies are an urban legend," he said. "You never hear of them anymore."

But you did hear about them in the 90’s. In 2000, Rutgers University released a study, Sex Without Strings, Relationships Without Rings, which concluded: "The mating culture for today’s twenty-somethings is not oriented to marriage, as it has been in times past, nor is it dedicated to romantic love. It requires no commitments beyond the sexual encounter itself, no ethical obligation beyond mutual consent."

Whereas before, a woman might have settled for fuck-buddy status when the guy she was interested in wouldn’t commit, the new woman didn’t just take what she could get—she took what she wanted. She made no apologies about the fact that she wanted to be done—well done.

The fuck buddy was the get-out-of-a-relationship -free card, a pussyport to no-strings-attached sex with unlimited rides. But as soon as the holy grail was within their meaty grasp, many guys found they’d rather keep their hands to themselves.

For women, the fuck buddy beat the one-night stand, easy. "It’s more in a woman’s favor to have a regular sex buddy," said Emma Taylor, co-author of The Big Bang. "The guy gets to know your body and what gets you off. It’s hard for a woman to orgasm if she’s sleeping with a guy for the first time, whereas a guy almost always can." In other words, the "buddy" aspect is key. After all, friends don’t let friends not get off.

On a recent Saturday night, I stopped by the bawdy saloon Coyote Ugly.

"People have started calling me ‘Mansley,’" said a pretty 27-year-old blonde named Ansley, "because I’m more of a guy than the people I hook up with. Tell me, when did all the dudes freaking turn into chicks? For my last fuck buddy, I made sure I chose a total player—and yet, once he realized I was only in it for the sex, he lost it. He actually screamed at me, ‘Listen, I am not a piece of meat!’"

A few stools down, a 25-year-old travel agent named Ashley was watching two beer maidens dry-hump each other on top of the bar.

"God, they all turn out to be pussies these days, don’t they?" she sighed, before downing a shot of Goldschlager. "I was sleeping with this guy, Andy, on a regular basis, but then he started getting too, you know, needy. I’d try to leave afterward and he’d be like, ‘Why are you leaving? Don’t you like me?’ Or if I wouldn’t let him stay the night, he’d accuse me of trying to ‘sexile’ him. The night he promised to fold my laundry if I let him stay, I knew I had to cut him loose."

Turning a guy into a fuck buddy isn’t as easy as one might think, as former porn star Candida Royalle discovered when she slept with an acquaintance. "I hadn’t made any bones about the fact that it was just sex, and we’d both had fun and thank you very much," she said. "Anyway, after I turned down his invitation to go out, he got so upset—he said he felt used and asked me how could I treat him like that and blah blah blah. I was shocked!"

The fuck buddy has a less crude, more prude cousin: the "friend with benefits." F.W.B.’s are more socially acceptable. When questioned by reporters, actress Lindsay Lohan (she of the Disney movies) even used the term to describe her relationship with a reputed actor boyfriend Wilmer Valderamma.

"A friend with benefits is a friend of yours that you occasionally mess around with," said Laura Leu, an assistant editor at Stuff. "The fuck buddy is just there for that reason; you’re not really friends with that person."

Scott Mebus, 29-year-old author of Booty Nomad, said: "Fuck buddies are more planned. ‘Friends with benefits’ just happens—like you help her move in, and then you’re both sitting on a box with a glass of wine and you end up sleeping together."

Of course, some insist that, by any name, neither situation is feasible.

"You can’t keep emotion out of repeated sex, you can only keep it at bay," said Matt Miller, a 28-year-old money-market manager. "One party always wants it to be more, and this is where animosity comes into it. The girl or guy who wants more—relationship, sober conversation, etc.—keeps f-ing the other party, liking and hating him/her at the same time."

"This one girl I knew asked if we could be friends with benefits—it sounds so sweet and innocent, doesn’t it?" said Daniel Isquith, who teaches high-school calculus on the Upper West Side. "But two weeks in, I was getting nightly phone calls ‘just to say hey,’ and I finally ended it when she vandalized my apartment because I didn’t invite her out with our friends one night."

This is where the F.B. triumphs over the F.W.B. An F.B. can grab an Amstel and the leftover lo mein out of your fridge, but there’s no going out for drinks or dinner or hanging out with mutual friends. (Hopefully there are no mutual friends.) F.B.’s know that snuggling should be reserved for couples in relationships and teddy bears in fabric-softener commercials. There is an implicit "don’t ask, don’t tell" policy and no date-y scenarios. Unlike with F.W.B.’s, you’re never privy to the other person’s extracurricular activities and, thus, not upset by them. The F.B. knows that when an F.W.B. sees their "friend" about to "benefit" from someone else, gauntlets will be thrown, usually along with a drink.

And yet: "I don’t know any guy who wants to have a fuck buddy," said Mr. Mebus. "Everything about it supports the female. Guys are looking for variety and women are the ones who want a relationship, and being a fuck buddy is a relationship, whether you want to call it that or not."

Why are men shying away from string-free shagging? A guy wants to believe that a woman isn’t really into casual sex as a general rule, according to Ms. Taylor, but that she’s making an exception just for him. "When the woman is just as excited about it as the man, he no longer has the feeling that he’s getting away with something," she said.

"Men enjoy being hunters," said Mr. Smith. "If we don’t get the feeling that we’re the lion peering through the grass ready to pounce, we tend to, uh, not."

But are they hunting—or just afraid of being hunted?

"The gender script between men and women has changed," said Dr. Anke A. Ehrhardt, professor of medical psychology at Columbia University. "What we hear in our newer masculinity studies is that men are not quite sure what the rules are, or what is the norm in 2004. Men say, ‘I know that women now want to be the initiator, but when it happens, it really turns me off.’ So there comes this insecurity and misunderstanding."

"Hypersexual girls kinda scare me," said Dan Madigan, a 21-year-old college student. "It sounds good in theory: What self-respecting dude wouldn’t jump at the chance of no-strings sex? But when it’s thrown right in your face, it can be pretty off-putting. When a guy is on offense, he’s only trying to please himself—pillage, conquer, etc. But when the female makes it abundantly clear that she too wants some romping good fun, then suddenly the possibility that we can’t provide is readily in our faces. An aggressive girl suggests two things: sexual experience and a demand to be pleased herself. These things are terribly frightening to a guy. Why do you think we all love 16-year-olds?

"Get this," he continued: "The last girl I had sex with told me ahead of time that she would only sleep over on the condition that I set the alarm clock for 9 a.m. on a Sunday morning, because she had a ton of stuff to do the next day. I thought she was kidding—until we both woke up the next morning for a little morning sex, and, within two minutes of completion, she had her clothes on and was out the door. No breakfast, no cuddling, no nothing. Needless to say, that was the last time we slept together."

But are women hopping out of bed so abruptly because, when they lingered in the past, they ended up getting burned?

"When guys include cuddling and pillow talk in the casual sex, women are often left wondering why the guy didn’t call," said Lorelei Sharkey, the co-author of The Big Bang. "If you know it’s just going to be sex, it’s easier on women to keep out the niceties."

Laura Strunk, a 26-year-old self-described "sexy female extraordinaire" who is a legal aid, agreed: "It seems as if there has been a movement of girls just wanting to use guys for sex, because we don’t want to deal with all the emotional-baggage crap—we can get that from our girlfriends. Guys seem to be taken aback by the bluntness of it all and then withdraw—literally. So it’s back to the vibrator."

"It’s a pride issue," added Ms. Sharkey. "The fact that the woman still just wants you for your body a month into it and doesn’t want you as a partner—it’s gotta be a blow to the ego."

"A guy’s gotta get the hell out before he gets his ass kicked," said Mr. Mebus, who admitted that he once bailed out on a fuck buddy when he started developing feelings for her. "Even emotionally well-rounded guys are not equipped to deal with that stuff. We’re meant to build things."

"It just goes to prove how utterly fucked up the male sex is," said 62-year-old Erica Jong, the author of Fear of Flying. "Men are trying to protect themselves from being hurt, and in a way, women are, too—protecting themselves from being hurt by taking on the male mannerisms. Our society is in the midst of change; people don’t know what their roles ought to be, and they’re making it up as they go along. It’s God’s little joke on the human race."

The other day at a party, I ran into my former fuck buddy, who confessed he’s now dating a 21-year-old virgin who lives in Michigan.

"I just think it runs its course after a while, and after the excitement and novelty of a new sexual partner wears off, it just becomes about the sex, and there’s something depressingly reductive about that to me," he said with a sigh. "But then there’s this side of me that feels really horny all the time and, to quote a man much wiser than myself, just wants to get drunk and screw."

As Mr. Isquith pointed out: "‘Friends with benefits’ is a great idea, but so was communism."  http://observer.com/pages/world.asp" title="http://observer.com/pages/world.asp" target="_blank"http://observer.com/pages/wor...