The wait is the worst. The fact that we would perform a giant group dance in front of 500 strangers and countless hi-definition cameras hadn’t really set in yet during rehearsals.

It has now, and nervousness is manifesting itself in all the usual ways; laughter, advice and the “Does that sound like kids? Do you hear kids?” question that someone asks every couple minutes.

We’re about to flash mob.

Flash Mob America, the for-profit company that has organized this endeavor for the benefit of the kids of Camp Modin, sure knows how to reel in dancers.

Like many addictive things, flash mobbing starts off with a low level of commitment, at first. Just put your name here, your age here, your email here, and bam, registered!

The first email I received July 18 was comforting and reassuring.

“Don’t worry if you don’t hear from us right away!” it read. “We Promise We’ll Get You Everything You Need the Moment it’s Available.” (Capitalization theirs, not mine)

On July 30 I received the rehearsal schedule. Four hours of rehearsals Sunday at XL Sports World Saco and then three more hours Monday. The location would not be revealed to us until the end of Monday’s rehearsal. Then the big event would take place Monday at 5 p.m.

The email even had handy links to instructional YouTube videos, which I played while getting ready to go to rehearsal and consequently absorbed nothing from.

Despite my inability to pay attention to videos, Sunday’s rehearsal went smoothly. I entered the Saco gym to find the most women I have ever seen anywhere in an assortment of workout attire. There were 8-year-olds with glitter scrunchies, teens obviously looking for a hip thing to do over summer break, soccer moms and retired older women. There were maybe 4 guys.

On the other side of the gym were the professional dancers. You could tell they were professional because they seemed way more comfortable in their Spandex and spent their downtime stretching as opposed to milling about like we did. They would start out the performance and be toward the front. We would make a giant, moving wall behind them.

Our dance teacher was Joi, an energetic dance teacher with Flash Mob America who was very patient with us, her new hapless yet eager students.

“So we’re going to start clap-clap-clap left-right 1-2-3-4-1-2- then we’re going to do the boom-boom-pat, yes?” Joi instructed while wandering through the crowd of 120 women and girls and 4 men.

“What are we doing?” a woman next to me asked? I shrugged. She shrugged.

Turns out we didn’t need to know anyway. Joi performed the routine in slow motion, singing the lyrics and performing the motions. It was like the dance version of singing along with the radio in the car. Everyone mimicked Joi and the effect was semi-coherent. We worked through the second song, Fall Out Boy’s ominously titled “My Songs Know What You Did in the Dark (Light Em Up).”

We were gathered up and told to show up Monday at the same place and after rehearsing for three hours, buses would take us to the top secret location where we would perform.

Monday’s rehearsal was a bit more frantic, because now the performance was a tangible thing that was x hours away. We rehearsed backwards and forwards and better-than-the-rest-of-us dancers emerged. During breaks, people mingled outside in the sun and at one point, one of the better-than-most dancers pulled her SUV into the grass and led a mini-practice of some of the more confused mobbers.

Gradually, the whole plan was laid out in front of us. The performance started with a Black Eyed Peas song, and then transitioned into the Fall Out Boy song. On Pete Wentz’s second command to “Light ‘em up!” the majority of the “mobbers” would join the professional dancers to surprise the summer campers.

We loaded up on the buses and the excitement was palpable. Then it began to level off. And then it began to fade. We waited an hour on the bus while the professional dancers rehearsed last minute and organizers figured out where everyone would go.

About 4:15, we got off the buses and hid as best as over 100 people can, preparing for the 5 p.m. showtime. I was in the middle of about 20 people wedged between two buses and some woods.

Slowly, the cameras showed up. One on some sort of forklift contraption, one on a tripod, a couple camera guys here, a …half dozen there. Oh my God, that’s a mini-flying camera.

Joi came over.

“Just to let you know, there’s going to be some CO2, cannon-type stuff, so if you hear it, don’t be scared and don’t run off,” she said, pointing at a pipe-sized cannon in front of us and angled above our heads. I half-wondered it the CO2 cannon was actually motivation for us to run out, like if someone got stage fright and decided to keep hiding instead, the cannon would scare them out into the open.

Suddenly, the women started giggling and we all caught it, joking about what 380 kids heading towards us looked like and the possibility of running out and being like a deer in headlights.

It got close to 5 p.m. and then it passed 5 p.m. We were antsy with anticipation. Joi ran over and told us to slide up against the side of the bus so we wouldn’t be seen prematurely. On edge, we followed the orders in less than a second.

Suddenly there were voices, little ones off in the distance and “Pump It” started. Twenty of us, most of us adult women, squealed like little kids on Christmas.

You can’t not dance to the Black Eyed Peas if you’re excited, and that’s what we did. Huddled and mashed against the side of a school bus we jammed to the music, getting pumped for our big debut.

And then 385 kids were running toward us. We couldn’t see them, but we could hear them, like the waterglass scene in “Jurassic Park.” The video screen beside us lit up. We could see them. The kids were so excited, many of them holding smartphones and recording their run. If they could have seen through the buses, they would have seen us all break into huge smiles watching them on screen because we knew we were about to surprise them yet again.

Fall Out Boy started blaring from the speakers next to us and my group collectively readied to pounce into dancing position.

“Light ‘em up, up up!” Wentz yelled and we poured forth. I don’t know what the kids thought because the only faces I could make out were behinds hundreds of smartphones recording us.

All the anticipation that built up over the last few hours erupted into maybe, a minute of dance. I guess that’s why we rehearsed so much, because I think I was so flabbergasted, I relied mostly on muscle memory for the actual dance moves.

We ended with our “robot powering down” move and that was it. Done. We applauded, the kids applauded and then Ahhhh! They were advancing on us!

The mobbers quickly fell back to the sidelines as 385 7-to-16-year-olds came forward. I was still trying process the whole scene but my eyes registered a movement near the ground.

A little girl camper that could not have been older than 7 had planted herself close as the other campers went around her, her hand outstretched to me for a high five.

We high-fived and she smiled from ear to ear before being swept back up in the camper crowd. We loaded on the buses and headed back to our cars, everyone still a little high from the experience.

We had flash mobbed.