At his 90th-birthday roast, Milton Berle and fellow cut-ups had them in stitches.

After 85 years of experience in show business, Milton Berle has some friendly advice for a photographer. ”No f — -ing pictures yet,” he growls. ”I’ll rap you right in the f — -ing mouth.” Not a move till Uncle Miltie’s good and ready. The comedian lights a massive stogie, pastes on a big smile, and utters his version of cheese: ”C — -sucker!”

It’s his party and he’ll swear if he wants to. We’re backstage at the Westbury Music Fair — a Long Island concert hall — for a taste of a fast-vanishing slice of showbiz life billed as ”Milton Berle’s 90th Birthday Roast” and ”A Tribute to a Legend Celebrating His 85th Anniversary in Show Business.” A handful of antediluvian borscht belters just subjected the star of NBC’s seminal Texaco Star Theater to a two-hour barrage of good-natured jabs.

”Milton’s at the age now where Angela Lansbury is jailbait,” cracked Dick Capri, 60, from the dais. Added 74-year-old Jack Carter: ”He [grew up] in the slums, only one bathroom on the entire floor. Now he lives in a gorgeous home, 10 toilets — and he can’t go.” And Sid Caesar, 75, said…well, we’re not quite sure. The Your Show of Shows star mostly babbled in his trademark pidgin French.

Then Uncle Miltie stepped up, and the sold-out crowd of 2,870 rose to their feet — at least the ones who could stand. These folks were old — there were more rugs here than at a Middle Eastern bazaar. And Berle was their hero, a guy who kicked off his career at age 5 in Charlie Chaplin’s Tillie’s Punctured Romance, did drag before RuPaul was a zygote, and dated Marilyn Monroe and Lucille Ball. At the podium, Berle struggled with the mike. ”There’s a switch: I can’t get it down,” as audience members roared and banged their canes. ”I got so much gas, I got Arabs following me.”

Arab jokes? Yes, these alter kockers could teach Howard Stern a thing or two about political incorrectness. Their freeze-dried-in-1958 routines were also laced with Polish jokes, south-of-the-border jokes (four Mexicans in quicksand is called cuatro sinko), Chinese jokes, gay jokes (they have a church called St. Francis of a Sissy), and, of course, Jew jokes.

Now, post-roast, Uncle Miltie has granted a few minutes to ”the Jew,” as he refers to this reporter. Since Berle is ”Mr. Television,” what does he think of TV today? ”That’s a cliched question,” he says. ”I don’t want to answer it.” Okay. How about revealing the secret to a long life? ”I never drank, never smoked a cigarette, been smoking cigars since I’m 12, and had a hard-on since I’m 10.”

A few pesky inquiries later, Berle takes control. He dictates how this piece should begin: ”’I wasn’t around in 1949, but as I read the history of TV, I wish I was,”’ he says. ”I won’t tell you how to write this. That’s just how I would write it if I was interviewing Methuselah.” A couple questions more, and it’s ”We’re done because I got to go.”