It is almost . . . repulsive - or, say, beautiful.

Under the blast of strobe lights, here at Tiffane's, wrists rub ribs, nylon knees acquaint themselves with gabardine thighs, fingernails rake necks, so slowly, slowly in these heavy-lidded heavings and twitchings which are the hottest new dance in town. It's called The Freak.

"Look, they do it in lines," deejay Gregory Diggs shouts over "Miss You" by the Rolling Stones.

Sure enough, first three, then five of them line up back to front with arms slithering forward around rib cages, drifting back to brush hips while everybody nestles into the sublest mime of a pulse whose ancient provenance is legitimized only by the most minimal of side-to-side time steps.

"I heard it came from Plato's Retreat," Diggs yells, as he cues up a record by Evelyn "Champagne" Davis. Plato's Retreat is a sexual encounter club in New York, not to be confused with Tiffane's, which is an L Street disco with a predominately black clientele.

"It's a dance that anybody can do, not like The Hustle," Diggs shouts. "And you can do it to any disco music. It's all the dances put together."

There's a guy doing a toe-wiggle a little like the old Mashed Potatoes, and there's a girl leading with her hips and you reach way back to remember The Twist. Except you didn't touch back then - that's what all the old folks complained about, right?

Let them do The Freak, a huge animal convolvulus down there - accompanied by strangely torpid faces, the sinking lids, the pouting lower lips - it's like the ultimate 1950's dirty boogie.

Contemplating it from the vantage of a side table, Bill Beavers, in pin-stripe jacket and cream trousers, wonders at it all: "It's like The Dog, or even The Twist," he says. "You know, those dances were illegal in some states."

In Baltimore, at Star's disco, they call it Body Language. In Philadelphia, at The Library, it's the Freaky-Deaky. Boston's Boston Boston disco is throwing a Freaker's Formal party, in which the invitation is cut in the shape of a tuxedo, and you have to reach inside the shirt to read the message.

"We haven't seen it yet in Los Angeles," says Cher 1 Song, who dances on Soul Train. "All the dances start in the East and move West. Out here, though, we had The Worm, and then The Spank, and they combined them to make The Sperm."

Says Philadelphia dance teacher Liza Slaman: "It's completely contradictory to The Hustle. That's gotten to be all gymnastics and it takes hours of practice. Now there's a rebellion, doing something completely uncontrolled."

Staring at the dance floor of Georgetown's St. Tropez, for instance, you can see the razor-cool formalities of the cocaine '70s giving way to, well, a couple closing on each other while the translucent floor pulses red and the sound of a song called The Freak by the Michael ZaggerBand rattles through the beige palm trees; "It's a body situation, it's a moving combination . . ."

She shimmies, tilting backwards while he brushes against her 'til she kneels.

"Sometimes it gets to be too much," says Artie Trakas, one of the owners. "It gets vulgar and we try to stop it by changing the music."

Katherine Marscio, who has invested a lot of time in perfecting The Hustle, watches from a table and says: "There's no challenge, you just stand in one spot. I mean, disco is an art." Her partner, Will Levine, fashionably decontracte in plaid shirt with necktie knot pulled down to his sternum, says in a bit of a Geogetown groan: "The Freak is something you don't do with a complete stranger."

At Plum, manager Mike Parrish says they get a lot of Freaking "when things get a little rowdy at the end of a Saturday night."

"It's the big dance," says Tramps' Mike O'Harro, who boats the curious distinction of being "disco consultant of the year in '75, '76 and '77.

But you know it's really big when you talk to Lindsey Flook-Stroup, who is 9.

Flook-Stroup herself does The Freak in the 5th grade in Stevens Elementary School.

"Last yer it was The Bump. Now The Freak has gotten big. We just do it anytime, whether we have music or not. But we don't touch. It's mostly 5th and 6th graders - the other kids are too young, I think."

At the L.A. Cafe it's closing time, and people are running out into the rainy night.

"Some people don't want to be touched," says a customer named John McCormick. "They give you signs. But some people do get real deep into it.It makes you more aware of yourself."

"God, yes," says doorman extraordinaire John Hoffman, who lolls on his stool dressed all in black, with gray tie, and the kind of eyes that look kohlrimmed when they aren't. "Sometimes if people aren't partying enough, I just drag them out on the floor and start Freaking with them."

"It doesn't have to eb Sir Galahad," says McCormick.

"I got dancing with this one girl, got really freaky with her dress, you know the way people run their hands around their hair and clothes. And she told me , honestly, that she actually had dreams about it that night.

Dreams! When's the last time a girl dreamt about an evening of dancing? When's the last time anyone was scared of a dance? It's been a while, in the post-Kennedy era of "eveything is permitted, nothing is real," as Hassan I Sabbah said.

Otherwise, . . . the advent of new dances has tended to be one shock after another. The waltz scandalized Vienna, with its strange notion of a man and woman dancing in constant contact. By the '20s, waltzing has calcified into dignity that the Charleston was designed to shatter, and since then we've had a series of dancers whose names are almost invariably indicators of their strangeness - the Jitterbug, which became approved church-youth-group stuff just in time to be superseded by The Bop, The Chicken (and The Funky Chicken), The Philly Dog, The Boogaloo, The Watusi, The Swim, The Popcorn, The Hustle, thousands of them to keep those of us who don't do them shaking our heads, and those of us who do, shaking, as the song says, our booties.

Maybe the Freak will take us over the cusp of prurience being so outrageous that we'll have to find a whole new future. Could The Freak mean the '80 are here? (And not a minute too soon.)

If you really want to think about it, check out Pier 9 late on a weekend night when the lights sprint their revolutions around the dance floor redbluegreenSTROBE! and they cut loose the carbon dioxide to turn it into some kind of thunderous heaven and the bodies are freaking and waving and it's like, ahhhh yes, the mother ship has landed, and there's room aboard for everyone.