It was friendly co-worker conversation - until Melanie abruptly brought up lurid details of her sex life.

One night, she and her husband couldn't find the sex toy they liked using. They finally found it, but it was broken. Then, Melanie giggled, they had to be much more imaginative ...

Experts say people who feel they have a license to spill these kinds of intimate details colloquially known as TMI, or too much information are taking advantage of a friendship, crossing boundaries and traumatizing casual acquaintances. But what motivates these unwanted tales? 

Seduction or Shock Value? 

Such behavior is like "diving into a lake without testing how cold the water is," according to Dr. Bonnie Jacobson, director of the New York Institute for Psychological Change and author of If Only You Would Listen

"For some people, it's a form of exhibitionism, even seduction," she added. "Like, if I show you mine, you can show me yours. On the other hand, they may not even be aware of what they're doing." 

These promiscuous disclosures are also the refuge of lonely people, according to Dr. Gerald Goodman, a psychology professor at UCLA. "We walk around with a basic need to be emotionally known," he said. "If we don't have a good source of empathy, we will then go to non-intimates" like casual acquaintances, he said. 

"The extreme case is a talk show like Jerry Springer, where we disclose our sexual history to the world." 

TMI tends to strike when it's least expected. In the middle of an innocuous chat, details are provided that leave the listener with an unpleasantly vivid mental image of their once-casual friend. 

"For some weird reason, random people I'm not even close with come over to my desk and shock me with these stories," said Sheba, who works in a production studio largely staffed by twentysomethings. "I tell them it's TMI and they laugh then keep telling me the stories!" 

"I think it has to do a lot with young people working together in a very lax and casual environment," she said. And sex has certainly become a more acceptable topic of conversation, a trend that reaches back decades but has been put on fast-forward by raunchy sitcoms and presidential scandals. 

Multimedia TMI 

TMI doesn't just apply to conversations. "The brother of the guy I'm seeing tells me his girlfriend took racy pictures of him," said Suzanne, who works for a New Jersey newspaper. "The next time I'm at her place, I ask about them, just for laughs. Well, they showed the Full Monty. I was flabbergasted. All night I couldn't look the brother in the face. ... If I'm dating someone I don't need to know if there's that much of a family resemblance." 

And new technologies have opened up new avenues for TMI. "There are some twisted individuals out there who like to find as many sick Web sites as possible," said Dost, an engineer working in Baltimore. "On a weekly basis, I get many pictures e-mailed to me at work of stuff that I really don't want to see. No thank you!" 

Anti-TMI Strategies 

Experts and victims alike agree the best way to stop TMI perpetrators is to set firm boundaries. "If the other person is offended or uncomfortable, it's inappropriate," Jacobson said. "But the person listening is just as responsible if they don't speak up. Don't think you're innocent here it's not just the speaker. The listener needs to say, gently, that this is more than they want to hear." 

"I tell people to stop," Sheba said. "Some get it and some don't. TMIers think if you have an open, outgoing personality then it's fine, you can say anything, no holds barred. But I don't ask (for it), so I don't welcome it." 

In the workplace, Jacobson adds, TMI behavior often qualifies as sexual harassment, and victims should take official action if the unwanted disclosures don't stop. "In the office you really better be sure" the listener wants to hear that anecdote about the handcuffs, "or you're facing a big lawsuit," she said. "You especially shouldn't talk about sex with someone who's at a very different power level: your boss, or a subordinate." 

Jacobson says men telling sexual anecdotes to women are a common source of sexual harassment lawsuits. "You don't want your insensitivity to jeopardize your ability to earn a living," she said.