For just the sixth time since she gave birth 11 months ago, Marquina Iliev was out of the house, and she was clad in tight, shiny black pants, writhing on Bowery Ballroom’s stage Rihanna-style.

Last night, Iliev competed in the northeast semifinals of the US Air Guitar championship, performing The Donnas’ raunchy number, “Take It Off.”

The 33-year-old Sunset Park resident, who works for a start-up in Soho building Facebook apps, used to perform karaoke – her specialty was death metal. But when a friend introduced her to the world of air guitar, she was hooked, even after that friend severed her pinkie toe in an air-guitar competition about five years ago.

“That’s why I wear these shoes,” said Iliev, pointing down to her steel toe boots. “Everyone’s performing barefoot, and I’m like, fuck that.”

Welcome to the wild, wonderful world of competitive air guitar. The dorky debauchery reached the Lower East Side following last month’s qualifier at Saint Vitus in Greenpoint and others around the country. The top three finishers among 20 competitors at the New York City semifinal would advance to the national finals next month in Los Angeles, with the hope of reaching the international finals in Finland.

Behind the scenes Tuesday night, the tight-knit community of competitive air guitarists resembled a Halloween party at a fraternity house – not the frat coveted by the Tri Delt girls but the one that always does well in the Greek Olympics, the one whose members clearly relish each other’s company.

In the green room, located at the top of a narrow, wooden, sticky stairwell, the smell of sweat and beer mixed with baby powder. Conversation was amusingly juvenile.

Not partaking in the dick jokes was Thomas Smolenski, partly because his girlfriend, Genavieve White, was next to him and partly because he was too busy getting his makeup done. Smolenski, 30, who was performing under the name Jean Luc Pickguard (a play on Patrick Stewart’s Star Trek character), had recently shaved his three-inch beard, and now White was tucking his shoulder-length hair into a bald cap, Stewart-style.

Smolenski, who organized and competed in the Brooklyn qualifier and lives with White in Greenpoint, has the advantage of dating a special effects makeup artist. As such, he’s changed characters many times since 2006, when he learned about the world of competitive air guitar through the news ticker on a screen in an elevator. Past iterations include The Wairwülf, Dean Razorback, Milo Rockerman, and Buzzthrill. This year, he performed “Oh No! Bruno!” by Nomeansno, a Canadian band, and ultimately came in fourth place.

Marquina Iliev (Photo: Brendan Lowe)

Marquina Iliev (Photo: Brendan Lowe)

The winner, meanwhile, was Mean Melin of Kansas City. After his opening round performance, shown above, he was assigned a Jefferson Starship song. Though his crowd-surfing attempt failed (he complained about a sore tailbone after the show) the performance was enough to head to the national finals in Los Angeles.

After the competition, Dan Crane, the production’s ringmaster, looked out at the mass of competitors and fans who had taken to the stage for the traditional closing rendition of “Free Bird.”

Competitors often refer to Crane, also known as Björn Türoque (sound it out), as a “living legend” and “the face of air guitar in the United States of America.” The 42-year-old starred in a documentary on the field, Air Guitar Nation, and wrote a book, To Air is Human, after quitting his job as an education software producer (his LinkedIn profile describes his experience with “database-reliant reading software”) to pursue air guitar.

Now he makes his living through hosting air guitar competitions, freelance writing, and a variety of odd jobs (last week, for instance, he served as an associate producer on a Showtime documentary about a teenager dying of melanoma).

“If I can inspire people to be ridiculous idiots and devote their lives to this,” he said, “it sure beats working in a fucking office.”

Top and bottom videos by Brendan Lowe