Polly Rodriguez bought her first vibrator at a Hustler Hollywood store off a St. Louis highway. You know the kind of place: pictures of women with fake breasts and peroxide hair, racks of corsets and "schoolgirl" skirts—making the whole experience feel unseemly and more aligned with a porn-imbued male view of female sexuality than how she saw herself.

So while still in her 20s, Rodriguez launched a different kind of sex toy company. Named Unbound and aimed at millennials, the brand radiates less "adult company" than it does approachable and feminist sexual wellness. On sale are its own line of vibrators with Smart Memory tech, subscriptions to sex toy deliveries and even a "Nevertheless, She Persisted" gift set complete with blindfold and Elizabeth Warren tote.

Unbound's formula has received mainstream venture capital buy-in, raising $2.7 million last year from such well-established tech-centric firms as Peter Thiel's Founders Fund. That size of investment was previously unheard of among the Women of Sex Tech, a coalition of more than 60 feminist-led startups, mostly based in New York City, with the goal of pulling their products into the mainstream realm of Lululemon or Glossier.

Yet none of this nuance matters to social media's advertising censors. According to the blunt rules that apply to adult companies on Facebook, Instagram, Snapchat, Pinterest and Twitter, sex tech is banned from paid promotion just like hardcore porn. And it's not because the rules prohibit nudity or overly sexual images, given the companies keep their ads PG. As Dame Products CEO Alexandra Fine says, "Our products don't actually look like anything"; her co-founder, MIT engineer Janet Lieberman, drew design inspiration for the company's vibrators from Oxo housewares and Google Home. In one ad Facebook rejected, the ambiguous object sits primly in a woman's outstretched hand.

The sticking point is the brand's products themselves. Facebook, for example, allows advertising of sex-themed products that promote "family planning" and "contraception," but not "sexual pleasure or sexual enhancement." That means condoms but not vibrators: "So we're implicitly saying it's OK for men to orgasm," Rodriguez says. "So why can't we have the same for women?"

Similarly, Snapchat doesn't allow "adult products" other than contraceptives. Pinterest's rules ban "adult products," and Twitter prohibits "sex toys."

"So every single one of the main staples of social media has doubled down and said, no, we have no interest in working with you guys on that," Rodriguez says.

Hulu, for its part, has been a bit more nuanced: An account manager wrote in an email last fall that Unbound couldn't show sex toys in the ad, but it was willing to review spots with non-sex-toy products like lube, massage oil or jewelry.

The result is that the new wave of companies pushing an elevated, female-centric view of sexual health is blocked from targeting new customers on the platforms most amenable to early companies. "Facebook and Instagram are good because you can start really small and scale it based on performance," Rodriguez says. "So for startups with limited ad budgets, [they would be] the most attractive platform."

Meanwhile, sex has sold nonsexual products since the beginning of advertising, as Dame's Fine points out: "There's bedsheet companies that are making obvious sexual innuendos, but my ad doesn't even mention sex."

The companies have no choice but to become crafty to advertise on web and mobile. Rodriguez's Unbound focuses on email and driving traffic to its content marketing blog, which covers topics such as gifting sex toys in the fraught era of #MeToo. The company occasionally pays evangelists to rave about its products on Instagram, and otherwise hopes that people will follow its Instagram and Facebook brand pages, which describe the company discreetly as a "website in New York, New York." (The companies can have brand accounts, a Facebook representative says, but the rules governing advertising are stricter given the content will be proactively shown to users.)

Fine from Dame says the company invests in paid Google search advertising, and she's found a semi-successful Facebook workaround: paying to boost posts from her own entrepreneur Facebook page of news articles in which she's appeared. They sometimes are allowed through—and she'll see $3 in sales for every dollar she spends, she says—and sometimes are taken down.

"I'd like to be more direct," Fine says. The indirect personality advertising "ends up making me look like a shadier person and that makes the industry look shady."

The sex-tech companies are optimistic that social platforms, which promote themselves as progressive brands themselves, will eventually come around. One did change its mind: Kickstarter rejected Dame's campaign for its first vibrator, but after Fine befriended some of the crowdfunding site's employees (its HQ is around the corner from Dame's) and argued "we're makers like anyone else," Kickstarter let Dame crowdfund for its second vibrator, Fin. It raised nearly $400,000.