Every day, adult video super-aggregator PornHub recommends a dozen or so scenes to those who visit its homepage. They typically go something like this (or involve some variation thereof): A naughty schoolgirl is seduced by her teacher (for misbehaving, naturally); a couple of straight girls are seduced by each other (for the first time ever); and/or a stepmother seduces her step-daughter (for some impromptu fauxcest).

All of this girl-on-girl action isn’t merely anecdotal either. In its annual January data dump, PornHub reported that once again, “lesbian” was the top search term of 2016, beating out “MILF,” “threesome” and even “teen.” The same was true in 2015. And almost true in 2014, when it fell a spot to the second most searched term of the year.

The “why” probably seems obvious: Two women are better than one, four breasts are better than two, etc. The lack of another male in the picture also means there’s no sense of competition. And of course, watching two women together plays directly into the ever-present male fantasy of being at the center of a threesome. But the experts say it’s more nuanced than that — i.e., unlike boy-girl scenes, girl-girl scenes stir the male libido not because of their sheer body-part count, but because they tend to linger on subtle movements like understated writhing or finely drawn o-faces.

Additionally, many men of a certain generation — let’s call it the Howard Stern Generation — came of age at a time when two women making out or having sex was becoming both ubiquitous and mainstream. They may have heard it referenced on the Stern show, seen it in clandestine copies of Hustler or Penthouse or watched it in movies (see: Wild Things, Cruel Intentions and Showgirls) right as their hormones were kicking in, full force.

All of which makes lesbian porn kinda quaint, especially in a modern porn era filled with extreme feats of face-fucking, anal sex and double penetration. “Porn is inching its way into being socially acknowledged,” says Bree Mills, an award-winning director and producer at Girlsway Films, which specializes in lesbian content. “Not necessarily acceptable, but fewer and fewer people are saying ‘I never watch porn.’ [Lesbian] is one of the most common entry points for people who are curious. They might not want to say, ‘Hey, I’m into Gaping Anal Princesses 4,’ but they might say, ‘Yeah, I like the pretty artistic erotic scene with these young female lovers.’”

“Pretty artistic erotic scenes” are also all about lingering kisses and more body-to-body contact. Plus, performers’ faces tend to be shown more frequently during the act, which, if they’re doing their job, are conveying pleasure. (Same goes for the sounds they’re making.) These details are what actually turn men on, says Shannon Chavez, a clinical psychologist and certified sex therapist — not the prevailing wisdom that they only want to see gynecological-like closeups and hardcore P-to-V pounding.

“Biologically, men’s sex response is wired to focus on what I call micro-expressions — a smile, a moan, a slight body movement,” she says. “That’s why it’s important to them to make a woman orgasm during sex. If a woman is enjoying it, the man is going to have a heightened arousal. His body is going to respond more.”

This factors into a guy’s porn preference through a highly intricate neurological process known as pairing. The first time a person experiences sexual arousal—whether from porn, a glimpse of flesh or something more abstract — that experience becomes lodged in their brain and associated, in one way or another, with their sexual desires.

That’s not to say that those connections are always — or ever — straightforward. “It’s not A+B=C,” says Cindy Michel, a psychotherapist who specializes in sex therapy. “It varies. For some men it might be, ‘I remember getting hard looking at this girl doing this,’ or ‘I remember watching two women together and something about it piqued my interest.’”

“I call it the arousal template,” Chavez adds. “It’s any emotion that stirs you. If we’ve been programmed to think something is wrong or naughty, that can be arousing. That can spark your whole sexual response.”

Which brings us back to Howard Stern and his painstaking descriptions of two women kissing in his studio as well as Wild Things and Cruel Intentions, where Denise Richards and Neve Campbell and Sarah Michelle Gellar and Selma Blair spent more time kissing each other than their male co-stars. Not to mention Jennifer Connelly and Kristy Swanson in Higher Learning; Gina Gershon and Elizabeth Berkley in Showgirls; Gina Gershon (again!) and Jennifer Tilly in Bound; Willow and Tara in Buffy the Vampire Slayer; Liv Tyler and Alicia Silverstone in Aerosmith’s Crazy; Harley Quinn and Poison Ivy; Britney and Madonna; Natalie Portman and Mila Kunis in Black Swan, Santana and Brittany in Glee.

If that’s not pairing in the making, what is?

The somewhat amusing irony of girl-girl’s popularity among the modern straight male, however, is that even as real lesbianism has become an accepted part of mainstream consciousness, most porn scenes still depict straight male fantasies rather than actual lesbian sex.

To begin with, women performing in mainstream lesbian scenes tend to look more like imaginary archetypes: long hair, big breasts, small waists, fake nails. “There are very few girls who have gone out of their way to look like a male fantasy that identify as lesbians,” says director, producer and actress Lily Cade, who calls herself “Porn Valley’s Gold Star Lesbian.”

Straight women performing lesbian sex also often don’t look that into it — something female viewers tend to notice more than male viewers. “The difference between men and women is, I can get around the physical, but they can get around the emotional,” says Cade. “I will have a bad time if the girl is gorgeous but not really into it, whereas if a girl is [gorgeous but] unhappy, guys can get it up anyway. It’s harder for them if a girl isn’t attractive.”

“I don’t know if you can say the female gaze looks different,” she continues, “but it definitely feels different.”

Above all, the lesbian sex positions men favor are more fantasy than reality. Obviously, there’s no one way that women have sex with each other, just like there’s no one way hetero couples or gay men have sex with each other. In fact, there are as many ways for lesbians to have sex as there are lesbians in the world. But some things still stand out. For instance, Cade says, scissoring makes an appearance in mainstream lesbian porn much more than it tends to IRL. “I’ve had girlfriends who like to grind — that’s a real sex act — but it’s rare,” she says.

Overall, lesbian porn for lesbians is less focused on body parts and sex acts than it is on relationships and specific scenarios. “We create this universe with characters, like what you would see on a mainstream soap opera,” says Mills of Girlsway Films. “When I’m producing, I’m thinking, How can I create a story with different dynamics and cast performers that really enjoy performing with other women?”

“Women are often looking for the type of thing that’s happening,” adds Cade. “Like, the woman is going to want to see office exploitation sex [for example], and is less likely to be just a fan of big butts jiggling.”

Women who identify as lesbians also want to see people onscreen who look like their peer group. Cade points to examples like the queer porn site CrashPadSeries.com, which features performers who “a lesbian could see and be like, ‘This could be my fantasy girlfriend.’”

Erika Lust, a director who was among the first women to create what’s now known as feminist porn, accomplishes this by careful casting and incorporating as much realism as possible into her scenes. “What you find with the majority of porn is that there’s a disconnect from reality,” she explains. “When I film lesbian scenes, the focus isn’t on the fact that they’re lesbians, it’s on the good sex they’re having. I direct them from my female perspective, and I explore female sexual wants and represent female sexual desire and pleasure.”

As far as why straight men might be satisfied with porn that’s more performative than real, Cade suggests — somewhat jokingly — that it might have to do with their level of discernment. “What I discovered is that men aren’t that picky,” she says. “I don’t want to be offensive, but they’re not. They’re satisfied with the terrible porn that’s out there. All you need to do is have, like, attractive women.”

Even so, she believes that most people do want to see real sex in which both partners are enjoying themselves. The catch is that when it comes to two women being together, most hetero men have never borne witness. “I think everyone is looking for it be real,” says Cade, “they just don’t necessarily know what real is.”

Then again, the fact that straight men are so easily pleased is in many ways a win-win for Cade. “Women don’t buy porn in anywhere near the volume that men buy it,” she says. “So when my work reaches the audience I made it for, I describe it as, I took straight men’s money and made subversive lesbian porn with it.”

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