"[Playboy is] not interested in the mysterious, difficult woman, the femme fatale who wears elegant underwear, with lace, and she is sad, and somehow mentally filthy. The Playboy girl has no lace, no underwear, she is naked, well-washed with soap and water, and she is happy."

-"Hugh Hefner: 'I am in the center of the world,'" by Oriana Fallaci, LOOK Magazine, January 10, 1967

“One thing I’ve always said was, a clean body means a clean mind. Sally’s mind was so clean it was bleached, just like her hair. Hah! Every time one of my little girls took a shower, I gave her a gold star. Sally had 184 gold stars. That’s more than any girl in the whole school. In fact, it’s probably the world’s record for showers taken in one day.”

-Voiceover narration from House on Bare Mountain, 1962

Nudies act as a wink at their audience: They are sly jokes about what the veneer of a narrative can do to civilize the sight of a woman’s naked body. Without the structure of a story, looking at her would be pornographic— prurient. But given a reason for her nudity—a reason of function rather than pleasure (for instance, taking a shower)—we can claim that what we’re watching is cinema, or maybe at least a nature documentary, instead of porn.

Cleanliness sits at an interesting intersection between the natural and social. All animals have grooming rituals; it seems like the most natural thing in the world for a person to strip off the costume of her clothing, scrub off the mask of her makeup, and return herself to the bare, clean fact of her skin.

But our understanding of what constitutes a “clean” body (something washed with soap, softened with lotion, and adorned with deodorants, at the very least) is a socially constituted set of norms; also, in the context of sexual desire, clean takes on the specific valence of healthy, and free of disease.

It’s precisely the shower’s transitory nature—the way it sits so squarely in the juncture between our animal and social selves, that it can prepare us to go to bed naked or blank our canvas for formal dressing up— that makes it such a vulnerable point. (Think, of course, of how elegantly Hitchcock played on the unease we feel in those solitary, intimate moments in Psycho.) It’s also what makes bathing such a perfect place to let a nudie linger: in the plausible deniability of nudity as natural, instead of something produced specifically to be salaciously consumed.

Pretending cleanliness gives the film its raison, its differentiation from porn. But it also gives the viewer something: looking at that clean, innocent, healthy, pink, twitching rabbit of a girl, the things he wants from her seem all the more deliciously dirty.

The question of art versus artlessness is what defines the contours of a nudie: the films must make claims to artistry, while simultaneously highlighting the artlessness of its subjects. Its female stars aren’t posing; they aren’t preening; they are simply, innocently, nude. Men make art about the nature of women. Who wouldn’t want to explore that geographic terrain?

Which is why it’s so critical that, per Playboy publisher Hugh Hefner, the woman in question appear to us mostly sans lingerie, or makeup. Those would be things she had purchased and put on herself; those are signs of an inner life and active sexuality that would shatter the nudie’s tenuous contract with the law, as well as its artistic contract with its audiences.

The woman on the screen might seem to have some kind of power, even in her nakedness—because of the sheer size of her, projected, or the fact that someone’s gone to the trouble to film her. In order to rebalance that, to make the men in the audience feel a little bigger, they must be given the sense that they are being given access to all of her: There’s no part of her that isn’t available.

A woman might make herself more attractive with lipstick or underwear. In a nudie, or the pages of Playboy, “well washed with water,” the promise is that she is guileless and stripped. She cannot trick you. She’s an innocent animal, and you, the viewer, well, you can’t help what you’re thinking. You’re just following the laws of your nature, after all.

Zan Romanoff is the author of two novels: A Song to Take the World Apart and Grace and Fever. Her essays and journalism have appeared in print and online for Buzzfeed, Elle, GQ, The Los Angeles Times, The New Republic, and The Washington Post, among other outlets. She lives and writes in Los Angeles.