Marlon Wayans (search) knows what hell is. "Hell is walking around for 60 days in a row with your thing taped back."

Marlon and his brother Shawn had to put up with the tuck-back - and more - when they dressed in drag for their new movie "White Chicks," (search) which opens Wednesday.

They're still unhappy about it.

"It was terrible," Shawn told The New York Post during a joint interview with his brother. "It's torture, man. That's what they should have done to those people in al Qaeda."

But all the pain will have been worthwhile if "White Chicks" does nearly as well as the Wayans brothers' last two movies.

Their raunchy and hilarious horror-film parody, 2000's "Scary Movie," (search) made a mint at the box office, grossing more than $300 million worldwide.

And while the sequel, 2001's "Scary Movie 2," was somewhat less successful, plenty of Wayans fans are eagerly awaiting "White Chicks," which reunites writer/stars Marlon and Shawn with their brother, "Scary Movie" director Keenan Ivory Wayans.

This time, the New York natives take on the eminently mockable world of Hamptons socialites, playing FBI agents who go undercover as a couple of snooty white chicks, loosely based on another pair of Manhattan siblings - Paris and Nicky Hilton (search).

While disguised, the Wayans not only have to dance to white-girl music (and pretend to like it), but even go along with the advances of various men.

In one scene, she-Marlon goes on a date with a big, horny dude played by former Philadelphia Eagles linebacker Terry Crews (search), who refuses to be dissuaded, even after Marlon cuts his toenails at the table.

Shawn, 33, had the initial brainstorm for the movie while watching "Legally Blonde" at his house in Los Angeles.

He immediately called Marlon, who has been his partner in crime since they were kids growing up in New York. Since moving to L.A., they have collaborated on projects including the mid-'90s WB show "The Wayans Bros."

Shawn is known as the idea guy in the family - "we call him the Rain Man," Marlon says - but this time his brother was incredulous.

"When he called me, I thought he was high," Marlon, 31, recalls. "I said, 'What are you smoking? And whatever it is, quit.'"

"Actually," Shawn interrupts, "you said, 'Whatever it is, can I have some?'"

Either way, the idea was born, and Marlon and Shawn took it to Keenen, their older brother and the one who got all his siblings into showbiz through his groundbreaking early-'90s sketch-comedy TV series, "In Living Color."

"Keenen's the genius," Marlon says. "If he says something's funny, it's funny."

This one got the seal of approval, and Shawn, Keenen and Marlon started getting together to write the script at each other's houses around L.A.

"Well, they never came to my house," Marlon notes.

"We did come to your house," Shawn says. "We had to get you out of bed."

Marlon didn't have much time to sleep during last winter's "White Chicks" shoot in Vancouver. The Wayans' work day started at 3 o'clock every morning, when they reported to makeup for the five-hour transformation process.

"I never knew it took white women five hours a day to get ready," Marlon jokes. "Now I feel sorry for them."

Step one was to remove as much excess body hair as possible.

"We shaved, we Naired," Shawn recalls. "We got the bikini wax."

"Yeah," Marlon says. "Shawn got the triangle. I had the Brazilian wax.

"By the end, we were both working the Buckwheat - you know, when you just say, 'I'm tired of this! I'm letting it grow.'"

Step two was an all-over airbrushing - covering their chests, arms, legs and faces with a bright orange-red acrylic body paint developed by makeup artist Greg Cannom.

"We tried just putting white makeup on them, but it made their skin look gray and ashen - really gross," Cannom recalls. "We needed this red to counteract their normal skin tone."

Cannom then attached four overlapping prosthetic masks and covered everything up with lots of thick Revlon ColorStay white-flesh colored makeup, which the company had sent over in drums.

After that came the fake breasts and all the cupping and tucking that the Wayans disliked so much.

"We had the man's version of a camel toe," Shawn recalls. "We started calling it the 'mammal toe.'"

"The worst thing about it," Marlon says, "was that we couldn't get excited if a cute woman walked by. It would have been a very strange feeling."

Not that anyone really got hot for she-Marlon or she-Shawn - "except maybe the prison inmates," says Marlon, who was considered by most on the set as the cutest white chick of the two.

"That's not something I'm proud of," Marlon says. "And Shawn is the better-looking black man. He should be on the cover of GQ. But as a white woman, he wouldn't make the cover of Field & Stream."

To the brothers' delight, at least one extra got fooled by the makeup and really thought they were women.

"Marlon walked into the men's room between takes and stood next to this guy at the urinal," recalls co-producer Rick Alvarez. "The dude bugged out. He just ran."

Clearly, makeup enough couldn't completely transform the Wayans. They had to act like women. To prepare, they both studied socialite mannerisms, watching movies such as "Clueless" and "Miss Congeniality," (search) as well as the classic drag comedy "Some Like It Hot."

"You have to get the voice right," says Shawn, switching to a high-pitched Valley Girl, "Ohmigod" sort of tone. "Like you say, 'Gucci is the most important thing ever!'"

"Or they'll start talking about world events," Marlon adds, "like about the poor, hungry kids in Somolia."

"They make me so sad!" Shawn says in his girl voice. "I mean, why can't I ever be that thin?"