FIRST STOP: The White House.

Metrobus number 112, pulls up the corner of Pennsylvania Avenue and Madison Place where, after stashing their beers under the seats, the 26 young men and three assorted girlfriends disembark.

The stop is a welcome relief for about a third of the men who, undoing their belt buckles, sprint off into the darkness of Lafayette Square. The rest charge across the street to taunt Iranians staging a hunger strike along the White House fence.

Screeching the National Anthem, they run up and down the sidewalk.

"Long live the shah," shouts Charles Halloran at an Iranian on the other side of the rope who smiles and raises his "Long Live Khomeini" sign a bit higher.

Soon they are back on the bus and the first Washington Interns for Hedonism tour of the city continues.

For no reason beyond having a party, Halloran and his two summer roommates, who also are Emory University students interning in Washington, formed the organization and rented the tour bus.

They invited a select group of new friends they met while making the rounds of bars that are important in the Washington subculture.

A stream of beer is trickling down from the two kegs at the rear of the bus.

The ad hoc committee of barroom cronies are walking down the armrests and lying in the overhead metal baggage carriers.

But they had paid for it -- $156 cash -- and the bus is theirs until 1:30 a.m.

It's Thursday night, which is almost the weekend. Thursday night is, typically, the rowdiest, most alcohol-drenched night of the week on American college campuses. And the leagues of college students who by day open mail and run Capitol Hill errands, have brought with them their native customs.

Next stop: E. J. O'Riley's Pub.

"The first thing you've got to understand is the rotation," says Jay Brown, Amherst '81, explaining the social rounds known intimately by Washington summer interns. "Thursday's E. J.'s; Friday: Chinese Disco (the Day Lily restaurant); Saturday: Third Edition; Sunday: Third Edition upstairs; Tuesdays is Chadwick's. I don't know what people do on Mondays and Wednesdays, maybe they rest up for Tuesday and Thursday?"

The "bus people," as they soon came to be known, file upstairs to the small dance floor where couples were dancing to a mix of the old California beach tunes and Motown hits spinning out from an album called "24 Happening Hits."

Around the dance floor are small tables, and at some of them are seemingly unattached women.

"alright, we've got some single ladies needing to be picked up," calls out Mark Parsells, who along with his roommates Halloran and Paul Pollack are hosting the bus bash.

A swarm of the bus riders, clad in uniform polo shirts, with a smattering of oxfords and even ties, fan out toward six key tables.

A thin fellow named Dave saunters over to a pretty blond chatting with a female friend. He soon strikes out.

But Brown is on deck, and in no time has pulled up a chair and is lighting the blond's cigarettes.

"God, Jay can do anything. It's amazing," comments another Amherst man. "It's got to be his upbringing. He's made of money three or four times over. He's related to the Chase Manhattan."

"That's it, back on the bus," shouts self-proclaimed tour director Parsells, an intern in Rep. Bud Shuster's (R-Pa.) office.

And as they crowd out the door, a 33-year-old who earlier in the day had finished his bar exam, sneers at the noisy youths. "They'll all be working for Covington & Burling in 10 years," he predicts.

The bus population has increased. Giggly newcomers include Laura, Robin, Gerry, Kathy, Bizzy, Eileen and Wendy, who, wearing a slinky pink dress, was carried aboard by Luke Reese, Washington Interns for Hedonism press secretary and a summer intern in Rep. John Ashbrook's (R-Ohio) office.

Next stop: The Capitol.

"This reminds me of a football game after we won," laughs a bus person. Soon rivalries crop up and a shouting out of colleges begins: Emory, Amherst, Princeton, Georgetown. And the fraternities: SAE, Sigma Nu, Sigma Chi, Phi Beta Theta.

Near the back of the bus, Brown is pointing out prep schools that well over half the bus riders attended: Lawrenceville, Groton, Taft, Exeter, Andover, St. Albans.

"Nobody from Choate, I don't know why that is?" says Brown who is working at Sotheby Parke Bernet this summer.

They are noisy and rude these sons of publishers, bankers, doctors and a federal court judge, but in a curious way they are the gentlemen their affluent upbringing would prescribe. Careening down 14th Street they shout crude obscenities out the window, but if a slightly saltly word slips into casual conversation with a young lady they apologize endlessly. When a full glass of beer is spilled on another young woman, she receives three offers to pay for her dry cleaning.

Near 11 p.m. they are still screaming and standing on the seats of the bus. Most have been drinking since 7:30 p.m. when the party began at the luxurious Georgetown apartment the three hosts have sublet for $800 a month.

In the apartment, an original Paul Klee painting hangs over a grand piano. But underneath the piano is one half of a $1,200 antique Queen Anne chair which Pollack, working this summer in the mailroom at the Dewey Ballantine Bushby Palmer and Wood law firm, says simply "snapped" one night.

Halloran speaks respectfully of a man known as Mr. Pritchett who rented out the apartment to the three. "None of this would be possible without him. He's in Cape Cod this summer.Thank God. We destroyed his place."

Good naturedly Barham pulls the bus into the Capitol parking lot, and the crowd runs up to the steps for three quick choruses of God Bless America and some snapshots.

Barham, meanwhile, thinks it's all quite funny. "I'm really enjoying it. Really," he says. "It just looks like they're having a good time. I just don't want them hanging out of the bus."

Halloran, an intern in Sen. Wendell Ford's (D-Ky.) office, says "the safety factor" was significant in the hosts' decision to hold their blast on the bus. Mr. Pritchett might also be pleased.

Next stop: Jenkins Hill.

This cozy, Capitol Hill bar was too quiet for this crowd. It's back to the White House.

This time someone has a pizza, and Halloran leans over the rope, takes a big bite, letting long stings of cheese hang from his mouth. "The CIA made this pizza. The shah made this pizza. This is American pizza," he shouts at the starving Iranians, rubbing his belly.

And after more of the same, Parsells rounds up the travelers, and they return to the corner of Madison Place and Jefferson Avenue where they had been let off.

But no bus.

Fifteen awkward minutes pass. Parsells says the bus just went around the corner and will be back in about five minutes. But privately he admits, "I don't know where the hell it is."

A park policeman then crosses Pennsylvania Avenue. "Hey, if you're looking for your bus, it's over there," he says pointing to the opposite corner of the Square.

Now it is after midnight, and the bus reeks of beer that sloshes across the floor when the bus takes a turn.

There also has been a human toll. At the back of the bus is a young man named John. His eyes are closed and he hasn't moved for over an hour.

"I can cure any alcohol problem," says Bill Chevailier, a University of Arkansas student interning at Sen. Dale Bumpers' (D-Ark.) office.

"Open your eyes. You've got to get up and walk," he coaxes. But there is no sign of life.

Stepping back Chevailier says "the worst thing is you pass out and get your stomach pumped. The second worst thing is you pass out and throw up. The third worst thing is you pass out and you have a bad hangover. That's him -- the third worst," he sums up then walks toward the front of the bus on the armrests.

Returning to E.J. O'Riley's, Parsells' crew tries for a few last minute scores. But by now it's after 1 a.m. and, like Cinderella, the bus people's magic night will end abruptly at 1:30.

A worried Greg Kaufman, Republican Senatorial Committee intern, checks his watch: "I've got to get a cab home. I'll never make it to work tomorrow. They'll kill me if I don't make it to work."

Last stop: Mr. Pritchett's apartment.

There are only 16 survivors who make the final leg of the journey. Without fanfare, many of the interns had jumped off and hailed cabs, or simply stayed behind at one bar or another. Reese is carrying out the kegs, while Parsells concerns himself with John's health. "Hey, somebody retrieve that guy back there. Is he all right, or is he comatose? Well, get the kegs out, that's the important thing."

But somehow John is able to sense that the bus had stopped moving. That the Washington Interns for Hedonism were disbanding. Slowly, grabbing the seats for support, he makes his way to the front of the bus past Parsells.

"Yeah," says the encouraging Parsells, "It's a long walk ain't it buddy."