FORT MYERS, Fla. -- The expression was first used this spring by Boston Red Sox manager Terry Francona, when talking about Victor Martinez, who is preparing for his first full season as Boston's every-day catcher.
"He'll have six weeks of Camp Tuck," Francona said, "which will either kill him or make him better."
Mark Wagner is 25 years old, one of the team's top catching prospects. Wagner attended the University of California-Irvine, where he said the toughest class he took was molecular biology.
And how is Camp Tuck compared to that class?
"The toughest thing ever," Wagner said, unable to suppress a smile. "Worse than that.
"And I did good in that class, got a B. I feel like I'm doing better in Tuck's class than I did in that because I actually enjoy this stuff and it's helping my future."
There is no registration form for Camp Tuck. It's by invitation only.
"It's like a privileged little group," Wagner said. "Only so many people get to do that. It's a matter of pride, because we do work our butts off to get there and continue to do so to stay there."
Officially, there are just six catchers enrolled in Camp Tuck: the veterans, Jason Varitek and Martinez; the organization's longtime catcher, Dusty Brown; up-and-comers Wagner and Luis Exposito; and Gustavo Molina, a nonroster invitee with a modicum of big league experience.
Another minor league catcher, a 22-year-old named Tim Federowicz, was recruited to join, at least for a few days. Ostensibly, they are attending spring training with the rest of the Red Sox, but they are a group apart.
"They're animals," said Gary Tuck, the Red Sox bullpen coach who oversees the camp within a camp. "They're in the weight room and they lift together. They're instructed to walk around like a pack of wolves, which means all six walk out together, all six condition together, all six drill together and they support each other.
"They're obviously different. They have to be different. The grind they have to go through in the course of a season is second to none. Pitchers grind once every five days. Catchers have to grind 24 hours a day."
There's another thing that separates catchers from every other position. "They're the only guy facing the field," Tuck said. "Everybody else is facing them."
Tuck, 54, has been instructing catchers for 34 years, first as an assistant coach at Notre Dame and Arizona State, then during a long apprenticeship in the minors before big league coaching stints with the Florida Marlins, New York Yankees and Red Sox.
"This is the best group I've ever had," he said. "From top to bottom, from the experience of All-Star catchers and the aptitude of the young kids, we have the strongest catching in the major leagues. And each one of them has the makings of a leader."
He includes Federowicz, who caught Jonathan Papelbon's bullpen session the other day.
"He's just a special kid, the way he carries himself, the way he handles the pitchers," Tuck said. "It's just a special group.
"Jason Varitek is a legacy in Boston history. He leads the young guys by example and words. Victor Martinez came on our team last year and stepped in and took off for us. Now he's going through this instructional camp. He said, 'It's like the army.' I said, 'Yeah, it is. My army."'
Varitek is the alpha "wolf," the leader of the pack. His name for Tuck, who has been the team's catching instructor for the past four seasons after serving in a similar role for the Yankees?
"The Catching Guru," Varitek said.
And the pack mentality?
"We're having fun with it," he said. "Every year, Gary comes up with a little twist. Every year he makes it a little more fun."
But behind the fun, there is a dead-serious purpose.
"I haven't killed anyone yet," Tuck said, "but the challenge is a tough one."
The core work is done in the drills. Catching soft balls smaller than a baseball with just three fingers, because those are the three fingers that manipulate the mitt. Catching tiny bouncy balls that Tuck throws at you rapid-fire, one after the other, so that if you take too much time catching one, another will fly right by you. Catching balls fired at your feet by a machine, teaching you how to block balls in the dirt. Catching balls while sitting on milking stools. Lining up across from one another, one on each side of the plate, one catcher mirroring the motions of the other in sliding from side to side, and dropping down to simulate the blocking of a pitch.
"They mirror each other for two reasons," Tuck said. "No. 1, when they go down to block the ball, it's a reaction drill. They react off each other. One guy leads, then the other guy leads and they alternate.
"No. 2, when they go down to block the ball, human nature says you're going to go down and look at the other guy, too, how quick he got there and how perfect his technique was. So you're actually pushing each other without really pushing each other."
There is the "team photo" -- no camera required.
"He gets us all in an arc," said Exposito, a strong-as-a-bull Cuban-American kid from Hialeah, Fla., "and shoots balls at us to block."
Don't forget "quick draw," in which catchers compete to see who can drop quickest to the ground. And then there's the ongoing competition for which Tuck keeps score: counting the number of pitches a catcher drops.
"I can't remember when I started it," said Tuck, who counts Joe Girardi and Jorge Posada among his former students during a stint as Yankees bullpen coach, "but it makes you cognizant of catching the baseball. I mean, you see your name on the board and you drop the ball, it's out there. It's out there for your teammates, and that's a big thing.
"The award for the drop contest is about this big" -- Tuck holds his fingers a fountain pen's distance apart -- "and costs about 10 bucks, but I'll tell you what. It's got their name on it and they'll take it home and whoever wins it -- Joe Girardi won it, Jorge Posada won it -- they'll put it among their World Series trophies.
"Why? Because it reminds them of how hard they have to work and how perfect you have to be."
Brown is in his 10th season with the Red Sox organization. After this season, he will be out of options, which means another team could claim him off waivers.
"It will obviously be big leagues or bust, so this is a big year for me," Brown said. "If I could jump into a backup role, that would be ideal. If that's not in the plans, then I hope to catch on somewhere else."
Brown is 27, a 35th-round draft choice. He made it to the big leagues last season for a brief but memorable stint. His first big league hit came Oct. 3, and was a home run off Cleveland's Mike Gosling, which earned him a curtain call from the Fenway Park crowd.
It was one of Tuck's favorite moments of the year.
"Dusty is a survivor, an ultimate survivor," Tuck said. "The Dusty Browns and Jeff Baileys of the world don't take 'no' for an answer. They quietly go about their work, and they make adjustments to be survivors and to become serviceable major league players.
"They're not sad sacks. They're big, strong animals who've turned themselves into players."
To understand Tuck is to know that he has affection for all of his catchers, whether they are All-Stars like Varitek or survivors like Brown.
"They know I love it as much as they love it," Tuck said, "and they feel my passion. It's a true passion. I care about each one of them, all of their families."
And now he has Martinez, who does not come with the behind-the-plate credentials of Varitek. Few catchers do.
"Victor has improved already this spring," Tuck said. "He came over with some bad habits. He'd been playing first base over there in Cleveland and was thrown in here with a new pitching staff. But he plays the game.
"He's attempting to make improvements in techniques every single day, and he's got some muscle memory things to correct along the way, but it's coming. It's a slow process."
It is for players like Martinez -- as well as for the Mark Wagners and Luis Expositos and Dusty Browns and yes, even the Jason Variteks -- that Camp Tuck exists. Tuck has gone to visit some of the best catchers in the business, from Johnny Bench to Mike Scioscia and Mike Matheny, to learn all he can about the craft, and to be able to pass on what he's learned.
"This is the only thing I've ever been interested in," he said, "my career of teaching and coaching."
Gordon Edes covers the Red Sox for ESPNBoston.com. Follow him on Twitter.