The first thing you learn is not to sit down.

"You don't seem timid," says the taller guy in thin wireframe glasses, one of the men—almost all men—milling around this place like it's their living room. "But I thought I'd warn you, if you sit down, guys will start flocking around you."

No, I'm not timid; my feeling on entering the Oregon Theater on Southeast Division Street isn't embarrassment but incredulity. We went because, though the Oregon has been in business as an adult theater since the '70s (it was built as a vaudeville house in 1925), no one we knew had ever ventured inside. The bowl of free condoms in the entryway should've tipped me off, but some prudish part of me believed those were for later, when couples go home. They're not.

The auditorium is concrete and cavernous, the insulation visibly crumbling from the high ceiling. The guy in the striped polo shirt showing us around is probably in his early 30s, making him the youngest person here by a decade. He points out the theater's fixtures clinically, detailing his plans to "fix the whole thing up"—exterior paint, restrooms, glory holes.

But I stop listening as it dawns on me what's happening: how low the film's volume is, how the uhhhnnns coming from the screen are virtually inaudible compared to the Uh! Uhh! UUHHHs coming from the people in the room, reclining on a hodgepodge of floral-patterned couches that serve as the only seating in the place. It smells of piss and sweat and the unmistakable scent of multiple patrons' cum.

The "couples section" is where the fucking happens. It's at the center, where men bounce around like molecules, desperate for something to do with their hard-ons. There, a fishnet-stockinged woman is positioned with legs up, splayed out on a couch, another woman's tongue plunged between her thighs. There are five guys jacking off in a circle around them, and I realize the porn is just white noise for the sex in the room. This is a meeting place for swingers, exhibitionists, voyeurs and curious hangers-on to get off and get each other off.

As soon as we walk in, my "strictly friends" friend and I are assumed to be among this group and sized up as such by the 20 or so patrons. As we pass by the tables up front where women sometimes strip or fuck for the audience, a man calls out from the couples section: "You guys coming in? You should come in and have fun!" Everywhere we walk, we're followed by shockingly short paces. Though the regulars we've spoken with have all been sincere, it's hard not to feel threatened when you're new to a space like this.

It occurs to me that this is what men hitting on women at bars would look like if all the pleasantries were forgone, leaving each person's sexual agenda laid bare with X-Acto knife clarity. That's just as refreshing as it is terrifying. A woman near us moans, her partner's hand down her pants. There isn't much for us to do besides leave.

Back in the lobby, one of the men who works here has chosen a Bigelow Sweet Dreams tea from the Oregon Theater's menu of refreshments: Pepsi products in Dart Solo cups, miniature Moon Pies, tiny tubes of flavored lube. He's on the company's Twitter account documenting the last thing we saw in that dark room: "Two girls, one double dildo," he writes.

He looks up and sees us heading out, offering a smile as accommodating as if this were some old-timey diner.

"You should've been here at 8," he says. "It was a madhouse in there." 

GO: Oregon Theater, 3530 SE Division St., 503-232-7469. Noon-late daily. $9, $6 for couples. Extremely NSFW: Visit @Oregon_Theater on Twitter.