Animators, it turns out, do it all the time.

They have been sneaking nasty messages and dirty jokes into cartoons for years. The reason the Walt Disney Co. has been fending off flak this week for subliminal scenes in the laser disc version of "Who Framed Roger Rabbit" is because of new technology, not new practices.

"Pepe Le Pew was known, on occasion, to indulge in inappropriate amorous affairs in certain frames," says celebrated animator Chuck Jones, former Warner Bros. director and creator of such cartoon personages as Pepe Le Pew, the Road Runner, Wile E. Coyote and Marvin Martian. "It was our way of slipping one past the producers. ... I had no idea that someday people would actually be looking for these things!"

The Disney flap was created when viewers freezing frames dur- ing certain scenes on the "Rabbit" laser disc discovered full frontal nudity, graffiti that advertises Disney CEO Michael Eisner's home phone number, and -- at a certain split second when Jessica Rabbit's dress flips up -- not undies, but just sweet nothing.

Animators report that such jokes will soon be found in decades' worth of cartoons. "This kind of thing has been going on forever -- those old animators lived for {erection} jokes," says John Kricfalusi, creator of the cartoon "Ren and Stimpy."

Homosexual jokes, heterosexual jokes, subliminal suggestions, double-entendres, visual metaphors, you name it -- single frames of smut have been smuggled into your favorite cartoons since their invention, artists say.

What's different is that in the old days, the dirty jokes were imperceptible. At normal viewing speeds, they slipped past at 30 frames per second, essentially invisible. Laser discs, however, make these quickie scenes much easier to find and freeze than on videotape or film.

"Tape is a tricky medium because it can expand and contract, which can result in fuzzy frames," says Jeff Mace, PC magazine's computer graphics project leader. "But like CDs, on laser discs you can track with remote control the exact frame you want to see and get an absolutely precise picture."

No guide to the "bad" parts of good cartoons will soon be in the offing, though. "It's hard to document this stuff because the film went by so fast that nobody noticed," said Jeff Lenburg, author of "The Encyclopedia of Animated Cartoons." "Nobody knows but the animators."

But now, what once had animators and their pals tittering in the production room is available to cartoon nuts and computer nerds everywhere who have the patience to search for it. One of the favorites among animators is a 1942 Warner Bros. cartoon directed by Bob Clampett called "Coal Black and the Seven Dwarves."

A satire of "Snow White" featuring African American characters, the cartoon is filled with double-entendres and lewd innuendo, with jazz tunes from the era as the soundtrack. But one scene stands out in animators' minds as a work of genius.

"Soul White, as she's called in the movie, is standing over the well singing, 'Someday My Prince Will Come,' and, like in 'Snow White,' an image of the prince starts to float in the water," says Kricfalusi. "If you look really, really closely, you can see the guy is masturbating!"

Representatives of Disney, Hanna-Barbera and Warner Bros. would not comment on these reports yesterday.

Cartoonists weren't the first to indulge in subversive sketches; it's a trick that artists have played on their pompous or parsimonious patrons for centuries. Giovanni da Udine, who worked in Raphael's studio, used to paint phalluses into commissioned paintings. He put them (surprise!) in still-life paintings of fruit bowls. More recently, Diego Rivera painted into a Detroit mural barely perceptible caricatures of his patrons after they proved stingy with funds.

"It's always been a wonderful secret," says Jones. "I was glad to see that the young animators at Disney still had enough spunk to do it." But he's worried about the future of the subliminal tradition. With cartoons like "Beavis and Butt-head" exploiting the crude up front, what could animators possibly sneak into their frames?

"Perhaps," Jones says, "they will have pictures of Mom serving apple pie."