I've known about my weight-gain fetish since before I knew I was gay. Sort of: The scenarios that turn me on are so far from sex—as sex was explained to me as a child (when two people really love each other, etc.)—that for years I thought I had discovered some kind of black magic. My fantasies were strange enough that the fact that they involved women seemed arbitrary. I learned to read very early partly so I could read the sexy parts of books over and over inconspicuously. "Hansel and Gretel" was a favorite. I say black magic because for most of my life, my sexual desires have made me feel like a monster. I might have struggled to remain inconspicuous forever if it weren't for a few enlightening Google searches.

Our body-image-obsessed culture makes my daily life a sort of scary, pornographic Easter egg hunt. The theme of weight gain saturates the media, conversations about it are everywhere, and grocery checkout stands are stacked with magazines that obsess over which celebrities are fat now. Imagine if the thing that got you off could appear anywhere at any moment. As a young teenager, when I realized I had a fetish, this was awful. Telling people I was gay was fairly easy for me, because in comparison to the other things I get off on, fucking another person who has a vagina seems mundane.

The first time somebody made me come, it was completely by accident. I was 19, and we were walking down Pine Street as she told me at length how over the past year she had gotten too fat to fit into her favorite jeans. "What's wrong?" she asked me when I stopped abruptly. I told her I had a foot cramp. Then I suggested we get pizza.

I wasn't ashamed that I liked fat girls (I was somehow spared that heap of cultural garbage). I was ashamed to want such power over another person. That is the main source of the excitement—the idea of controlling someone from the inside out, or witnessing a fundamental loss of control that allows me to imagine myself in a position of power over them. I was in love with the girl who made me come on the street, in a tender high-school way. But then again, to derive pleasure from something that obviously made her unhappy felt ugly to me. I thought no one would want to be with me if they knew I had those thoughts. But I couldn't help myself.

I didn't tell anyone until I was 21. It took me half an hour, cringing under a pillow, to say anything besides "I have to tell you I'm into something weird." My girlfriend tried guessing: "Operation Ivy?" And then, when a seagull flew by the window, "Birds!" Finally, I told her. She didn't break up with me. She didn't tell me I was disgusting. She took me out to dinner. I felt like a new person. In general, the way that people I have dated have reacted when I tell them my big scary secret gives me hope for humanity. Somehow, it didn't occur to me that someone might enjoy knowing a way to get me off as reliably as flipping a light switch. I just wish it hadn't taken me so long to tell someone.

My encounters with people who share my interests have all involved the internet. It is so much easier to tell someone you're into this kind of thing if you know they're into it, too—i.e., you're both on a website devoted to it. It's also easier to talk about if you've done a bit of research on your own time. The porn I like most is made by people who have the complementary kink—women who get off on gaining weight and want others to witness the process. I am an atheist, but the fact that people exist who not only get off on such an obscure thing, but also showing others that they're getting off on such an obscure thing, makes intelligent design seem almost plausible. And it seems that many fetishes complement each other in this way. I'm reminded of the rare ghost orchid that can be pollinated by only one species of moth.

These videos on YouTube and Dailymotion document weight gain in various ways—measurements, weigh-ins, and conspicuously outgrown clothing are popular. I personally like nothing more than a girl splitting a button-down shirt over a period of months like a busted home-run baseball. Often, they look like they're going to masturbate as soon as they're done filming; sometimes they look like they're about to do something unimaginable. At the end of one video, a woman tilted the camera up to reveal she was wearing clown makeup. Once, I had just gotten off when the camera angle changed so I could see the woman filming herself had very few teeth. Her laughter looked positively evil. I was genuinely frightened, but I liked her.

Some of my girlfriends have gained weight for me, some just talked dirty to me about it. Of course, there are always questions, such as "Are you calling me fat?" (the answer is either no and you're gorgeous or yes and you're gorgeous) and "How much would you want me to gain, ideally?" (not enough to cause health problems and not more than you're comfortable with) and "Are you only attracted to fat girls?" (no—though I like them a lot).

I'm not sure how unusual my fetish is, but on websites devoted to it, like Fantasy Feeder and Feedism.net, people frequently post things like "Is anyone from Glasgow online?" One night, my Gmail video chat box popped up, and there was a naked girl eating ice cream. All she said was, "You're cute." I have no idea how she found my e-mail address. She finished her pint of (I think pistachio) ice cream while we both beat off, and then she disappeared. I had a series of similar Skype dates with a woman in Manhattan who was in grad school for social work and loved Oreos. There was talk of meeting in person, but then we both found more conveniently located girlfriends.

When I was invited to a Fantasy Feeder meetup a few months ago—at the Cheesecake Factory, obviously—I was terrified. What were people like who were like me? What would we do? I hoped something would happen, but I didn't think I was ready for a frosting-covered orgy with strangers. I think most of all I was afraid these people would somehow confirm that I was right to be ashamed of myself. They did not. They were very friendly, and for some reason, all eager to talk about Dr. Who. There was a tall, possibly albino guy who looked like a beautiful ghost. The only person who gave me the creeps was a guy in a poofy Renaissance fair shirt who hit on my date relentlessly. When she said she wished she could just eat and fuck for days at a time, he said, "You just need a guy with a lot of stamina." "Or a woman," I said, "any woman at all." Everyone ate a lot, more than seemed physically possible. It was exciting that no one there knew what we were up to. My date got three kinds of cheesecake, and we went to a hotel.

She was 20, from a small town, and had never slept with a woman before. She said she was on Fantasy Feeder because people had always told her she should diet, but she liked being fat. She wasn't into gaining. It seemed she liked a particular body type and found the site to be a convenient means of shopping for it—teenage boy or perhaps elf bodies, considering she picked me? She was working on a degree she hoped would get her a job designing artificial limbs, but she was currently taking a photography class. She took some pictures of us that would endanger my political aspirations, if I had any. I stayed with her for two days. The second morning, we drank hotel instant coffee naked in front of our window overlooking Puget Sound. We watched the city appear as a fog burned off, and I felt a tremendous sense of possibility. We kissed, and then I went to school. I won't deny my fetish is a little monstrous, but then, what sex isn't? I don't feel bad about it anymore. I'm a nice monster, mostly—so let's get pizza.

Sarah Galvin is a poet, currently pursuing an MFA degree at the University of Washington. Her poems can be found in iO, Dark Sky, PageBoy, and Alive at the Center, a Northwest poetry anthology. Shockingly, she also writes food reviews.