Bill Blass, who wasn't wearing Bill Blass, got himself a drink, lit a cigarette that he held like a blackboard pointer, then began explaining how you don't need to be a millionaire or even rich to afford his designer clothes.

"I have an airline stewardess who shops at Neiman's," he said in a proud voice that somehow didn't sound like his hometown of Fort Wayne, Ind.

("I got out as fast as I could," he explained.)

"And then you changed your accent," observed Val Cook, the vice president of Saks-Jandel.

"Daaaaahhhliing" responded Blass pleasantly, "you know I've aaaalllways taaalked like this."

This was one particular hallway conversation occuring at a party held by Washington Post Co. chairman Katharine Graham last night. It followed a Post-sponsored fashion symposium that benefited the Hospital for Sick Children. Designers Blass, Pearl Nipon, Donna Karan and Oscar de la Renta had talked to 800 of the fashion-conscious at Georgetown University and then afterward, some 100 people had a buffet supper at Katharine Graham's R Street home.

It was by and large a well-dressed crowd wearing new fall clothes or one of the evening's designers. And the designers, used to seeing their clothes on hangers and mannequins, reveled at the live bodies.

"Oh, there's a lady in a cardigan coat with a georgette lace blouse," said Albert Nipon, who's married to Pearl and runs their business. "And one of the girls is in a red and black checked dress with black braid. And there's a girl in a red blazer with a navy and white dotted georgette."

This last georgette belonged to Ellen Morrell, a teacher of retailing at Georgetown. "I can tell through your coat that you're wearing my dress," said Pearl Nipon, who patted it as if she were its mother. Come to think of it, she was.

Earlier, during the symposium, Nipon had remarked that she designs for women who in middle age, alas, find themselves shaped like pears. This remark caused lively debate at the party, particularly from middle-age women who looked more like carrot sticks.

"I'm 47, and I haven't changed with age," said Patsy Larrimore, the director of nursing at the Hospital for Sick Children. She, for one, said she didn't mind being likened to a celery stalk.

"Yes, they do look like pears," Nipon continued to assert as she gobbled her seafood crepes. "They don't look at themselves. I look like a pear."

"I look like a pear and I'm not even a woman," added Andrew Bergstein, an NBC advertising executive who was standing nearby and gobbling seafood crepes, too.

Eating mini-crabcakes was William McDonald, vice president of marketing at Woodward & Lothrop. He sells Bill Blass, and here, according to him, is what the Bill Blass woman does on weekends:

"She's a little more luxury-casual than beer-drinking and crabs," he said. "She spends at least one Saturday a month by the country club pool with martinis."

Other guests at the party included Edwin Hoffman, chairman of the board of Woodward & Lothrop; Mayor Marion Barry and his wife, Effi; and Helga Orfila, a former fashion model and wife of the secretary general of the Organization of American States.