Why the long face?

Be nice to the monsters and furry things at Halloween Town this weekend. They are new to this.

In fact, it was just a few days ago that they learned how to be Teenage Mutant Ninja Turtles, calico cats, and the Big Bad Wolf.

On Monday night, in a room at the Boston Medical Center that is usually used for people taking childbirth classes, two dozen volunteers and one reporter sat like good pupils as we learned from the master, a man named Kevin Roberge.

You don't know Roberge, but there's a chance you have rubbed his paws. For much of his life he has worked for Walt Disney as a costumed character in its theme parks. He has been tigers and dogs. He has been an over-excited genie.

"I can guarantee I am in more photo albums than anyone here," he told the group, as we prepared for more than an hour of costume boot camp.

This is Roberge's first time helping out with Halloween Town, a two-day event that turns the Seaport World Trade Center into a 70,000-square-foot holiday theme park to benefit Boston Medical Center charities. The event is meant for children younger than 12, so most of the costumed folks are furry as opposed to freaky. Last year more than 10,000 people showed, so this time around the BMC hired a professional - Roberge - to help volunteers make the H-Town experience as legitimate as possible.

As Roberge told us, being a theme-park entertainer in a big suit takes skill.

"It's not like you just throw something on and wave," he said.

Our training began with stretching, because, as it turns out, costume heads are heavy and can cause injuries. Roberge explained that before you put on an oversize head, you should take one hand and gently pull your head to one side while the other hand is straight out in the opposite direction. Then, you slowly lower the extended hand. That loosens up the neck.

Next, we were advised on our wardrobe. Roberge recommended that we bring about seven T-shirts to the event because we would sweat through all of them. Also, he said, we should wear loose shorts.

If you find that you are getting cold in a costume, that is a very bad thing, he said. You might be passing out. You might be dehydrated. If you're in trouble, stomp three times so that a non-costumed greeter can find you. (Stomping three times is the universal costume code for "get me out of here," Roberge said.) Unless absolutely necessary, he said, do not remove your head; it can scare the tykes and ruin their experience.

And with that, he brought out a "friend," a massive head belonging to the Big Bad Wolf. Abby Zorbaugh, 21, was the first volunteer to try it on for size.

She placed the big head on top of her own small one and bobbed from side to side.

"How does it feel?" Roberge asked.

In a muffled voice she answered, "Like I'm blind."

She was asked to cover her wolf eyes and ears. She didn't quite know where they were.

Next was Matt Hoffman, 19, who tried on the head of Calico Cat. He couldn't see much either but was a bit more confident about emoting.

How does a stuffed creature show it's hungry if it can't speak? (The answer: It rubs its tummy.)

How does a creature show happiness? (It waves, put its hands on its hips, and moves its arms.)

The most challenging task was figuring out where to look when someone is taking a picture. After all, you're not looking through your eyes. Most likely your real eyes are the mouth of your costume head. Roberge says it's worth spending a few minutes in your gear before meeting the children to get a sense of how to fake like you're looking straight ahead.

"People will say, 'Goofy, what are you looking at?' " Roberge warned, advising us to make sure we practiced keeping our face in the right place.

Next in the training: learning how to cope with kids who want to be mean to you or take off your head. If children kick you, you cannot kick back.

"Even if you're a turtle with ninja skills, you can't retaliate," he said, rather seriously.

In those moments, retreat and stomp three times.

And, when in costume, it's best not to pick a fight. Confident costume wearers may get the urge to tease adults, but be careful, Roberge said.

"Don't take off people's hats," he said. "Some people don't have hair there."

And, of course, costumed furries should be good to one another. Under no circumstances should they consume Doritos before wearing a shared costume - especially Cool Ranch Doritos. The smell never leaves the suit.

Neither does alcohol or cologne.

"It will smell like Obsession the first time, but it won't a month later," he said.

Most importantly, Roberge said, people in costumes can't hide pain or sadness. The real professional theme-park actors learn to put their troubles aside. They're actually smiling in there.

"When you're sad inside a costume people can tell," he said. "We're doing this to make people smile."

Meredith Goldstein can be reached at mgoldstein@globe.com.