Must love dogs” is popular biography-box standby on pretty much every dating site. To normal people, it’s just a boring, reductive way of supplementing your personality — or lack thereof — with an inoffensive, statement of interest in fluffy animals (seriously, stop it).

For members of the leather-clad puppy play community, “must love dogs” is really a prerequisite to understanding a how members (known as pups and handlers) feel sexually and emotionally fulfilled.

The UK’s Channel 4 has a new short documentary called Secret Life of The Human Pups examining pup play culture that airs this week. You can check out the trailer below — the full doc will probably be available online for international audiences in a few days.

Pup play is a very specific sexual fetish, sometimes seen as a subsection of leather play and BDSM. Most of its practitioners are gay men, but people of all genders enjoy donning various dog costumes and playacting at canine life to various degrees. Much of the time it involves sex, but it shouldn’t be confused with zoophilia (directly wanting to bone animals) or bestiality (actually boning animals), or even furry culture, which has different rules, and customs.

The documentary focuses on Tom, a man who goes by Spot when he’s dressed in his white dalmatian suit, following him to the Mr. Puppy Europe competition, a modeling competition and roleplay convention in Antwerp, Belgium. Tom told the Guardian that living part-time as a pup allows him to shrug off the worries and responsibilities of adult human life and enjoy the company of his “owner” or “handler” in a simple, primal context.

You’re not worrying about money, or food, or work,” Tom told The Guardian. “It’s just the chance to enjoy each other’s company on a very simple level.”

“Puppy play is exactly that — play. There is an immense amount of pleasure from gamboling around in a club playing with squeaky toys because you’re making people laugh, you’re being a cute little puppy,” David, an academic and writer who participates in Pup play told the Guardian. “The gay scene can be very serious, scary and off-putting. But if you’re going in with a little puppy hood, ears and a tongue, you look cute. You’re allowed to bound around and be enthusiastic, mischievous and friendly.”

Spot in his suit. 

Like many fetishes, pup play develops very early in life, though many pups and handlers might not fully express themselves until they’re well into adulthood. If certain acts or behaviors become sexually linked in a developing child (which is a natural progression) for human sexual development.

Miss Minx, a female pup, told SF Weekly that she was always interested in roleplaying as a dog, even as a child, but had a gradual awakening to the world of pup play.

“I didn’t know what it meant to me until later in life,” Minx said. “I read about pony play in a book, and animal role play became something real that I had to try.”

The website SiriusPup.Net has several explainers on human pup play (but might be a little NSFW, fair warning), and explains that sometimes the play does not take a sexual tone:

Allowing someone to explore aspects of themselves may be fun, but what’s erotic about it? Sometimes it is pure role-playing with no erotic component, because when a pup is a sleepy pup, there is rarely any sexual interaction. For others they may seek discipline in pup play so they experience dominance and submission which is the turn-on in itself. The pup is always a human pup capable of frisky human sexual behaviour with other pups or their owner. Woof!

Sex scientists think fetishes arise in one of four ways. They could be a result of “brain overlap,” where regions of the brain that govern sexual behavior are close to those that control other regions of the body (like feet, a common fetish) or emotions. The Pavlovian theory is also common — repeated association with something in a sexual context leads to that thing (like inanimate objects) taking on sexual properties of its own. Other theories include the “gross out” theory — that sexual arousal weakens the disgust factor and lets us see things we’re usually grossed out by, like feet or even weirder shit (sometimes literally shit), as sexy. Similar to this is the pain theory, that the sensation of pain gets all mixed up with pleasure in states of heightened sexual arousal.

“I’ve heard of everything from feet to dirt to cars,” Dr. Justin Lehmiller, a sex educator and research psychologist at Harvard University told Shape magazine. “Pretty much anything you can think of, someone out there probably has sexual associations attached to it.”

So looking at things that way, a bunch of people dressing up in dog outfits and playing with one another starts to seem more normal. The simplicity of life as a dog is certainly easy to understand, even if some of the more, er, animalistic activities that go hand in hand with it aren’t. But hey, dogs like to hump stuff, so why shouldn’t people who feel most comfortable pretending to be them get to have their fun too?