It takes a man with balls the size of that rolling boulder in Raiders of the Lost Ark to verbally ravage dapper Don Draper. Don is a paragon of virility and, to paraphrase the great Raymond Chandler, “Every man wants to be Don Draper and every woman wants to be with him.”

But Roger Sterling, Draper’s devil-may-care boss, could give two shits about all that. “You don’t know how to drink,” he tells a crestfallen Don. “Your whole generation, you drink for the wrong reasons. My generation, we drink because it’s good, because it feels better than unbuttoning your collar, because we deserve it. We drink because it’s what men do.”

Who’s got the big cojones now?

“He’ll say whatever occurs to him and take what comes,” says John Slattery, the man who’s brought Sterling to super-suave life. “In the 1960s, there weren’t half as many rules as there are now. Half the things Roger says would land him in jail.” He pauses. “Sexual harassment jail.”

But after six and a half impeccably crafted—and acted—seasons, the doors of Sterling Cooper are on the verge of closing for good. Yes, the final seven episodes of AMC’s Mad Men, dubbed “The End of an Era,” begin unspooling April 5. Since 2007, Matthew Weiner’s show about the personal and professional ordeals of the employees at Sterling Cooper, a 1960s advertising agency on New York City’s ritzy Madison Avenue, has captured the cultural imagination with its vintage finery and embattled characters.

And lording over the posh proceedings—or rather lurking in the shadows with a big, shit-eating grin on his face—is its master of ceremonies, Roger Sterling; a man with so many wonderful quips they literally filled a book.

“There was a ritual,” Slattery says of getting into Roger mode. “You get your hair shellacked, get dressed in that three-piece suit, and it straightens you up. Then there’s a distance from the trailer to the stage where you get your brain around what you’re about to say. Then you show up and the prop guy, Johnny Youngblood, gives you your ring, your cigarettes, and your lighter, and you make sure you’ve got all your shit. Then you’re immersed, and ready to go.”

It’s the eve of the long goodbye, and the 52-year-old actor is perched on a couch by the window of a Manhattan hotel suite. He is, by all accounts, relaxed, and has come to terms with the “end of an era.”

“Given that they haven’t aired yet, and nobody’s started critiquing it, I’m satisfied,” he says. “I think Matt did a hell of a job with the ending. It ends the way it should end. It’s no mean feat to tie up all the loose ends. People are going to have opinions and they’re not all going to be good—they never are—but I’m ready to move on.”

Slattery has many fond memories of his time in glass-clinking ’60s New York. “Oysters,” he says matter-of-factly. “All the scenes in bars and restaurants! But there are also a few coming up that are among my favorites.” When asked if he’s ever tripped on acid—another very memorable, ass-baring Sterling sequence—he unleashes a heavy grin before pleading the Fifth.

Among the things he’ll miss the most is the rich rapport he’s cultivated with Christina Hendricks, who plays the fiery secretary-cum-partner, Joan Holloway, of whom Roger once famously remarked, “I am so glad that I got to roam those hillsides.” Roger and Joan’s star-crossed “will they or won’t they” relationship has long been one of the show’s more fascinating subplots. And when we last left them, she’d finally let Roger back into her—and their son’s—life.

When asked whether or not he thinks Roger and Joan, whom he calls “sexually mercenary,” belong together, Slattery isn’t so sure. “There’s the Jaguar incident, plus she gets pregnant and he’s not really there,” ponders Slattery. “Maybe it was Roger’s way of getting thrown out, like guys will do. I’m going to act like such an asshole that she’ll throw me out, and I won’t have to break up with her. Christina’s said that if Roger had gotten down on one knee and proposed a season or two earlier, Joan would have gone for it.”

He adds, “I’m not so sure about that. I don’t know if they’re meant to be together. One of the best things about the show is it’s not explained why they’re not together. There are always people who look back and think, ‘This is the one that got away,’ and it’s usually for no good reason.”

Slattery also had the pleasure of directing several memorable Mad Men episodes, including Season 6’s “A Tale of Two Cities,” which sees Roger rock an ascot and embed with Hollywood hippies. It also features the return of a mustachioed Danny Siegel, played by Danny Strong. Since the series’ premiere, Strong has become a major Hollywood power player, penning the scripts to The Butler, two Hunger Games films, and serving as showrunner of the Fox smash, Empire.

“That’s Danny Strong who punches me in the balls!” he says of the L.A. episode. “That guy is on top of the world right now with Empire. If he reads this, ‘Danny, I need a job!’ He actually asked me if I wanted to be on Empire, and I think I let that ship sail. I don’t know who I would’ve played… some white dude.”

The journeyman actor also fondly reminisces about all the hard partying the cast did throughout the show’s seven-season run. As soon as filming wrapped on the series last year, he says, “Everybody showed up, changed their clothes, and the party started.” They brought in the show’s dedicated bartender—whose name escapes Slattery—to make drinks in what proved to be “an emotional, long night.”

But the goodbye soiree paled in comparison to the first few seasons. And once you get Slattery going, he’s off to the races.

“In the early years, anything was liable to happen,” he says. “We’d be partying at a hotel and the pool would not be off-limits. We had some wild parties. This was a group that didn’t need a lot of encouragement in that regard. But that’s changed. People have grown up. We started this when my kid was 6 years old, and he’s damn near 16 now!”

Then, a sinister smile. “Matt, Hamm, and I went to Vegas once. That was… you know,” he laughs, censoring himself. “Just what you would imagine. A lot of… card-playing. Hamm’s a good card player, I’m a shitty card player, and Matt’s somewhere in between.”

Sterling and Draper aren’t just best pals on the show, either. Midway through my interview with Hamm at the same hotel hours earlier, the door slowly creeps open and both our heads swivel toward it—only to be greeted by a demented-looking Slattery flipping the bird. “What’s up, nimrod!” yells Slattery. “Hiiiiiiiiiiiiiiii, OK, bye,” he continues, before slamming the door.

“Jon and I hit it off on Day One,” says Slattery. “In the first scene, all we had to do was a long walk into where Joan is saying to Peggy, ‘Here’s what you do, put a paper bag on your head…,’ and we were riffing on that dialogue and just screwing around. We had a similar sense of humor and really hit it off.”

While Mad Men is done and dusted, Slattery and Hamm will soon reunite on Netflix’s upcoming series Wet Hot American Summer. As a parting gift to himself, Slattery took the desk lamp from his desk, which currently resides in his office. He also meant to swipe a suit, but forgot until it was too late. Hamm, on the other hand, “really didn’t want anything and wanted to just walk away,” Slattery says.

Despite his many years playing a bon vivant onscreen, Slattery claims Roger hasn’t rubbed off on him at all. “When I was younger, I’d like to have fun and go out in New York,” he says. “These days, I just want to go home and hang out.”A pause, then that grin again. “But I don’t hate a martini.”