Might strip too enthusiastically. calima portraits

It's not easy for 18 dancers to simultaneously remove their tops while standing in a row on a small stage. Last week at Fred Wildlife Refuge, during a rehearsal for the Heavenly Spies' 10th anniversary show, choreographer and dancer Fae Phalen suggested that half the women leave their tops on.

"I feel like it would be a better line with all our tits out," another dancer argued. In that case, Phalen said, everyone might have to perform this four-minute closing number "without a bra on." Some of the top-heavier dancers groaned. But bras, Phalen pointed out, make everything more complicated. Rhinestones and lace don't often peacefully coexist, causing weird shapes and catches in the costumes. Plus, Phalen worried that if the dancers strip too enthusiastically, people in the front row might wind up with brassieres in their desserts. But you can't let the bra limply drop either—hooks tend to gravitate toward fishnets. "I've had to do half a dance with a bra hooked to the side of my leg," Phalen warned her crew.

But the protestations grew and Phalen relented, adding nude bras covered with rhinestones to the number, straining an already-stretched costume budget. Phalen promised to bring glue guns and a bag of rhinestones to the next practice. Forget diamonds—glue guns, it turns out, are a girl's best friend. Everything from feathers to lace can be slapped onto a costume with a little hot glue, and a few of the dancers have nasty burns to show for their recent costume adjustments.

Considering the frailty of flesh, a 10-year anniversary is a big one for any dance company—and perhaps especially for a burlesque troupe. The Heavenly Spies formed in 2003 when a group of Cornish dance students, led by the ballet-based Phalen, decided to put on a monthly show in the back room of Sonya's Bar and Grill on First Avenue. Every month, Phalen choreographed a new set, and they slowly evolved from an all-purpose dance revue into their burlesque-heavy repertoire. In 2005, the Heavenly Spies moved their act to the then-new Can Can Cabaret and started performing weekly.

Phalen's choreography sets the Spies apart from other, more amateurish burlesque you could see around town on any given night, where dancers waste time between a few simple steps and discard clothing whenever a number gets boring.

A Spies striptease is all about control. Every movement—from the tilt of a hand while pulling off a glove to the arc of a swinging ponytail—is planned and practiced to perfection. Corrie Befort, a local modern dancer and choreographer, most recently of Salt Horse, explained that Phalen's choreography provides a "sense of form and an aesthetic" that you don't usually find in burlesque—"like white cake made with real cream," Befort wrote in an e-mail. "I was totally lured by the sugar, but hooked by the quality."

I've been a Spies fan since I first saw them at the Can Can in 2006, but I worried that sitting in on a rehearsal would be like getting a magician drunk and listening to him slur out the secrets to all his tricks. But watching Phalen lead 18 women—many of them new to the Spies, a few with classical ballet training, and of all sorts of body types and sizes—through the creation of a dance routine was more revelatory than ruinous. It took four hours to hammer out the details of this four-minute number, with Phalen conducting a symphony of details with equal measures of artistry and pragmatism.

She began the rehearsal with a vision for the whole routine, but she took plenty of input from the dancers—an intuitive process informed by years of experience. A few of the moves were too complex for 18 women to maneuver in an eight-count, so Phalen cited the old Heavenly Spies motto—"less heave, more ho"—and found a simpler, sassier solution.

After finally nailing down the basics of the closing number, more than half of the dancers headed home, leaving the six official Heavenly Spies to stay behind to work on their solos. Phalen and longtime Spy Kimberly Galore practiced a chair dance, and Galore tried out a new number she'd been choreographing that involved four feather boas hot-glue-gunned to her ass and some double-time booty shakes.

Diamonds represents a ridiculous amount of work for Phalen and the Spies; all this preparation is for a stand of five shows over three days, featuring 20 dancers (18 women and two men) performing 13 new numbers and four of "our old favorites," set to live music from the Bang Bang Band and singer Caela Bailey. It's one of the biggest shows Phalen has ever choreographed, and it represents what could be the start of a new direction for her, away from straight-up burlesque.

"I like the idea of doing more showgirl kind of stuff," Phalen said. Rather than going through the same old striptease, she imagines the dancers coming onstage in pasties and launching into the kind of elaborate, heavily choreographed routines you see in big-time Vegas shows.

She's going to need a bigger glue gun. recommended