A masked man in gleaming white satin, silver sequins and a pointy cap topped by a white ostrich feather blasted on a police whistle and waved his rhinestone scepter. The voice at the microphone boomed "It's Mardi Gras!" and the band launched into yet another round of "Dixie," compelling congressmen and constituents alike to stand on their chairs and cheer.

Heads turned and more cheers echoed as the man of the moment, Vice President George Bush, stepped into the chaotic fray that was Saturday night's Washington Mardi Gras Ball.

"It's marvelous, spectacular," Bush beamed from the pink spotlight glare as he escorted a young and blushing Mary Lyon Johnston, queen of the ball and daughter of Sen. Bennett Johnston (D-La.), on a regal procession. b

But Bush and official Washington were quickly forgotten as this simulated New Orleans Fat Tuesday got seriously under way.

Johnston and her king, the dour and besequined 60-year-old Charles E. Brown, led a mini-parade ground and around the Washington Hilton ballroom. Perched on a towering pink and silver throne, their means of locomotion was a cabal of costumed men who strutted, dipped and jived to tunes like "When the Saints Go Marchin' In."

After the royalty came the Boeuf Gras" float, a litter bearing a golden bull and rendered a bit shaky as its carriers, armed with cardboard meat cleavers, continually paused to lift their face masks and gulp drinks proferred by jubilant bystanders.

The traditional Mardi Gras dictum, "throw me somethin' mistah," was all you could hear as clumps of plastic beads and silver doubloons (emblazoned with the theme for the ball, "A Love Affair with Louisiana") plummeted every which way. Women dressed to thrill, strappy and strapless in chiffon, taffeta and the ever-abundant sequins, fell to their knees and groveled for the souvenir trinkets.

Sen. Russell Long (D-La.), wound up and red-faced, talked excitedly about the mystik Krewe of Louisianians, the sponsoring organization for this annual ball away from home, and reminisced about the 33 others that have proceded it.

"I was the one who started this, I put the krewe in the ball," said Long, who is captain emeritus of the Mystik club. "It brings our people together from north, south, east and west more than anything does."

Sue Huckaby, wife of this year's ball chairman, Rep. Jerry Huckaby (D-La.), gave Long credit for starting the event her husband dubbed "the social event for people in Louisiana."

"This is Russell's baby," said Sue Huckaby, a vivacious and beautiful Southern belle. "For years, it was held out of his office."

She recalled a nightmarish experience from her first Washington Mardi Gras. During the initial ceremonial dance sequence, after which partying krewe members present there lady partners with fancy gifts, she got relegated to wallflower status.

"Our first year here, I didn't get called out to dance," she said. "After that, I made sure I got called out."

The traditional gift after the dance is a silver (plated) goblet. One unidentified belle unwrapped hers with great sighs and smiles.

"I have five children at home, and this is like having one more," she cooed.

The ball attracted a good number of non-Louisianians in addition to the entire home state congressional delegation, minus Rep. Gillis Long, including Sen. Robert Dole (R-Kan.) and his wife, presidential assistant Elizabeth Hanford Dole; Reps. Trent Lott (R-Miss.) and Jack Kemp (R-N.Y.); Sen Alan Cranston (D-Calif.); Secretary of Treasury Donald T. Regan, and Secretary of Energy James Edwards.

The boyish Rep. John Breaux (D-La.) could hardly contain hmself as he celebrated in a booth where Mumm's Cordon Rouge champagne corks popped with regularity.

"It's an absolute, total zoo," Breaux said.