Elvin W. Moon had it down to a graceful art. Standing at the base of an escalator at the Washington Hilton, he managed to answer questions about his vigil, stuff a photocopied article into every passing hand, advise the owner of each hand, "Here, read this!" and get back into starting position before the next set of fingers arrived.

"It's very effective," said the Los Angeles business consultant, attending the 15th annual Congressional Black Caucus Legislative Weekend, about his self-advertising campaign. "I'm getting very positive feedback -- Here, read this! You got one? What did you think about it?"

"Very interesting" came from an anonymous mouth and Moon said, "You hear what he said?"

Moon also had deposited the article -- a Los Angeles Times story about the growing professional clout of young black urban professionals ("buppies") in which he was quoted -- on every available Hilton surface. "MY COMMENTS! FOR YOUR READING AND COMMENTS" he had written next to his quote about his study that showed 76 percent of black professionals in private industry are frustrated because they feel they will not be promoted.

"I've been always talking about the same issue -- we should help each other, not depend on someone else," he said. "The current administration is not putting any emphasis on affirmative action. I don't believe in quotas but I do believe in affirmative action. I'm taking it to the people and hope we can put some pressure on the government."

And there were plenty of people to take it to. Caucus leaders estimated that as many as 15,000 people attended the forums, panels, working groups, symposia, roundtables, practicums, hearings and brain trusts, not to mention the receptions, brunches, breakfasts, fashion shows and dinners. They expected to raise $1 million for fellowships and other educational projects.

"Maybe after this weekend the president might believe that some of us do have constituents," said Rep. Charles Rangel (D-N.Y.). "We are sending a message to the president. He may have said some disparaging things about black leaders, but 10,000 people just don't come to Washington for a social affair."

Over the years, members of the caucus and the black leaders, business people and others who attend the weekend have become increasingly displeased with the label "social affair." The "Midnight Champagne Fashion Show" and the "Brunch Fashion Show," where fluid models sweep down runways to the cheers of the audience, are always the weekend's most popular events, together drawing 6,000 people.

"I think there's been a tendency to stress the fashion show," said Dorothy Height, president of the National Council of Negro Women. "But if you think about it, most major decisions are made over food. It's the custom in this country. People want to discuss business, they say, 'Let's have lunch.' But when black people do it, we act like it's something unusual."

As one attendee put it, "It's fine to be social, as long as you're networking."

Small green cards littered the tables at the Saturday morning prayer breakfast.

"All we ask you to do as a symbol of your commitment to your brothers and sisters in South Africa is to sign your name on this," said Caucus Chairman Mickey Leland (D-Tex.).

And they did, 2,000 people writing their names on the cards bearing the South African seal and the words "Pass Book."

Sunkist Orange Soda, Coke, Stove Top Stuffing, candy bars, key chains, posters, Christmas cards from McDonald's, hair mousse, corn chips, packets of Hawaiian Punch, a "Getting to Know Your Letter Carrier" coloring book. Free Stuff. What is a convention without Free Stuff?

But among the more than 200 companies, government agencies and private groups contributing to the large exhibit hall were several companies that a recent caucus publication listed as having business connections with South Africa. At a convention where the theme was "The Reality of an Interdependent World" and where there was much anger about South Africa and the Reagan administration's policy toward that country, the presence of those companies displeased some.

"We are getting a bit concerned about that, but we as a caucus have decided not to be unreasonable," said Leland. "The issue has come to public attention so recently. We have seen some companies slow down their involvement in South Africa. We've seen some leave South Africa. When we find there are companies that are obstinate, then we'll act . . ."

No mass event is complete without stars to keep the crowds excited and the caucus provided several, starting with itself. At the awards dinner Saturday night, the 19 congressmen and one congresswoman who constitute the caucus lined up like a triumphant home team on a spotlight-dazzled stage to the cheers of nearly 3,000 in the International Ballroom and another 1,500 who were watching the proceedings from the Crystal Ballroom via closed-circuit TV.

William H. Gray III (D-Pa.) was the obvious caucus favorite (any reference to his work as the first black Budget Committee chairman rocked audiences into instant applause), but wherever one looked there seemed to be a caucus member posing for a picture with a grinning supporter.

There was ABC's Ted Koppel, in attendance to receive an award for his week of "Nightline" broadcasts from South Africa. There was Coretta Scott King, who, much to the distress of her staff and two high-heeled policewomen providing security, stopped to talk to every passerby, reporter, maid and "Do-you-remember-me?"

And just to prove that even if you weren't invited to the "Very Special Reception" thrown by Anheuser-Busch on Saturday you could still rub up to the Great (or at least the Famous), "Miami Vice" costar Philip Michael Thomas showed up at the mass-admission reception and charmed a good section of the crowd by willingly posing for "Just one picture, please!" and asking each trembling woman by his side what her name was.

"Oh, Jesus!" one woman moaned as she got in line for a picture. "I will die! Jesus!"

Bob Geldof got straight to the point.

"I know you haven't given awards to white people before," said the British organizer of Live Aid after receiving the CBC's Chairman Award. "So I'm first, you know . . ."

The audience cheered at that, as it did when he asked "those of you in power" to make sure the U.S. government helps the starving in Africa, that "it doesn't pull back, it doesn't stop, it doesn't impose conditions on the aid because you impose conditions on people who can't meet it."

South African Rev. Allan Boesak was scheduled to speak at the awards dinner, but after his recent release from prison he was confined to his house and had to send his greetings by telegram, which Gray read to the audience.

"Time after time, they are seen to be on the side of the oppressor, in spite of the lofty words and moral condemnations," Boesak wrote of the U.S. government's policy toward South Africa. "But I am convinced that there is another America. An America that remembers its own struggle, that cherishes its freedom and dignity, that therefore understands the aspirations of an unfree people . . . It is to that America that we appeal. And you are that America."

It was the appeal that Gray responded to in his speech.

"Allan, there is another America," he said. "And we're going to watch to see what happens with those executive sanctions. And if the Krugerrand ban is not imposed within the next week or two, if the bank loan prohibition is not enforced, and if the fair-employment principles are not enforced, I can tell you, Allan, that the other America in the House every week will give the Senate a chance to vote on stronger restrictions on South Africa . . .

"Yes, we've come a long way," Gray said as he neared his conclusion, his voice growing louder and more forceful, "and Allan Boesak, there is another America in Washington, and it will not rest, it will continue to work, it will continue to say no to the voices of injustice, it will continue to work to change America's foreign policy until we have one standard. And so the Statue of Liberty will no longer look simply to Europe and say, 'Give me your tired, your poor." It will look South, it will look to the Caribbean . . ."

And as Gray roared his last sentences, the men and women in the audience roared back, cheering, applauding, rising to their feet in a wave of sound that swallowed up the final words of the speaker and continued long after he left the stage.