In recent years, this war has become easier to fight. Lammily, the doll nicknamed “normal Barbie,” now comes with period accessories. This summer, a woman ran the London Marathon without a tampon, bleeding onto her running pants. HelloFlo ads are adorned with hashtags like #MakeItVagical. In 2011, a British artist created the “Menstruation Machine,” a sort of high-tech chastity belt for men who wanted to experience the feeling of having a period.

Here’s the thing, though: Most of this taboo-busting is being driven by women, who are making peace with their bodies and dragging something considered shameful into the open. Men are welcome to belong to this movement, and to contribute to it. But for Finley, that’s not enough.

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If the woman proudly embracing her period is slowly emerging as a cultural trope, it’s long predated by the trope of the man who’s laughably clueless about the whole thing.

In defense of the moon guy and the butt guy and the hold-it-in guy, a lot of men learn about periods by piecing things together on their own. In one 2011 study, researchers asked a group of college-aged men to describe how they had learned about menstruation. The responses had a few common themes, the authors observed: The men had largely picked up snippets of knowledge from female family members and, later on, girlfriends, but by and large were still fuzzy on the basic mechanics of the female reproductive system. “Boys’ early learning about menstruation is haphazard,” the researchers wrote. “The mysterious nature of what happens to girls contributes to a gap in boys’ knowledge about female bodies and to some negative views about girls.”

At any rate, it makes for okay comedy. See here, here, and here for riffs on the same idea: LOL, guys don’t get periods. It’s one model of a limited number of models for the ways men can talk about menstruation: ignorance, or an academic interest, or even a fetishistic one.

Finley’s doesn’t fit into any of the models. A man who lived and breathed period kitsch for so many years is not ignorant, but neither is he a scholar. His curiosity doesn’t stem from anything sexual, either: “With girlfriends, the subject never came up. And if it did come up, I think I would have run,” he told me. “I just wasn’t interested.”

Finley traces his interest back to the identity it created, the chance it afforded him to be a little subversive. “The museum was kind of an act of freedom for me,” he said. “I grew up in a military family doing everything right, the straight and narrow. When other kids were swearing and stuff, I never did.”

His attraction to all things menstruation began when he was living in Germany as a graphic designer for the U.S. military in the 1980s. He started collecting old menstrual-product advertisements, he said, because the artist in him liked looking at renderings of women’s faces. But as his collection grew, that appeal was supplanted by what he called “the buzz of the forbidden”—the more ads he amassed, the more he felt like he had finally discovered the rebellion that eluded him in his early life. Here, finally, was a way for him to flout the rules.