That lonely tan-and-green box sat in the middle of the conference table in Chicago, the focus of the gathering, and yet the very thing nobody wanted, literally, to touch.

Normally, at meetings like this, the dozen or so marketers for the ad firm Euro RSCG would be inspecting the packaging and planning to take away samples to try in advance of working up potential advertisement campaigns.

This time, though, they were being asked to help sell a new enema—one essentially intended for recreational use—about to come to a drugstore near you from the at-home colonic king C.B. Fleet Inc.

“There was that look on the faces like, ‘You’ve gotta be kidding me, we’re talking about anal douching?’” recalled Rose Cameron, chief strategy officer at Euro RSCG, of the first strategy session last October. “Then eventually we said, ‘You know something, it’s a fact of life, get over it. What’s the best way to approach it?’”

In doing so, Cameron’s team set a new cultural benchmark for addressing hard-to-discuss topics, writing yet another chapter in a long history of advertising that, in the modern age, seems to be confronting and pushing past taboos and barriers at a faster pace than ever before. With the ads for Fleet Naturals, the firm concocted amusing analogies to a person’s butt with images of a donkey, a pair of hamburger buns, and a train caboose above the tagline “Keep It Clean. Naturally.”

It’s clever and, since Portfolio.com broke the news of the product introduction and marketing effort last week, the ads’ images have spread virally across the Web to warm acceptance. In fact, the reception has been so positive that it would be easy to forget that it was only a decade ago that Americans were first uncomfortably confronted with ads for drugs that addressed impotence.

Since then, marketers have taken on body grooming, sexual lubrication, and now, as Cameron put it, anal douching.

“There was a time when toilet paper ads were hard to do,” said Michael Sanzen, chief creative officer and co-founder of Concentric Pharma Advertising, who worked on the first wave of Viagra ads for Pfizer Inc. in the late 1990s while with the agency Cline Davis & Mann. “You couldn’t do ads for brassieres on TV. But what we’ve learned is that it’s really the lack of conversation that leads to all the uncomfortable feelings around it.”

It would seem that we’re over that now, what with the incessant drumbeat of personal confessions and frank chatter on reality TV and blogs as well as podcasts and satellite TV where the FCC has no jurisdiction. And still, in the traditionally conservative advertising industry, the approach always begins with the creation of a parallel language and training audiences to understand the implications.

For the sake of marketing Viagra ads, for instance, Pfizer invented the term “erectile dysfunction” to displace the stigmatized concept surrounding impotence. In the Fleet example, the buzzword is clean and fresh even as the company’s market research showed that the reason why many people use enemas when they’re not instructed to by their doctors is to clean out prior to anal sex.

“They can’t speak of it in everyday language because some people may find it offensive, so they talk about it in a different way,” said Mason Wiley of the L.A.-based ad placement firm Hydra. “It’s one step removed than the way you talk about it with your friends. But they don’t want to provoke a backlash by being too on the nose.”

Another common technique, as seen in the Fleet ads, is to disarm viewers with humor. Cameron said alternative ads that were tested were copy heavy and talked about how natural it was, but they were “ho hum. Humor breaks down all barriers.”

That also was the approach for Procter & Gamble when the company decided to market the disposable Gillette Fusion razor as well as Braun’s Body Cruiser electric shaver as tools to be used in shaving, among other parts, the genital region.

Gillette, for instance, tells male customers in sections of its website as well as on YouTube that “trees look taller when there’s no underbrush.” Interested guys then may view an instructional video featuring a cartoon man offering shaving tips and referring to the prospect of gaining an “optical inch.”

“We wanted to make sure we did it with cartoon characters in silhouette to make it lighthearted,” Gillette spokesman Michael Morton said. “It was a level of discussion about body grooming that people were comfortable with.”