If the White House press is a group of rowdy campers spending the lazy end of summer here between the mountains and the sea, then Larry Speakes is their cabin counselor, the man they see each morning and sometimes call for at night.

He can be firm, like the morning everyone wanted to hear about the attack of the Libyan aircraft.

Speakes: "This is not for cameras."

Reporter: "Why not?"

Speakes: "I'm too sleepy."

Reporter: "Are we going to get anybody on camera?"

Speakes: "No."

Reporter: "Never?"

Speakes: "No."

Reporter: "No Meese?"

Speakes: "No. No president, no Meese."

Reporter: "Doesn't he want to talk to the American people?"

Speakes: "I don't think he does."

Speakes can be reflective: "I'm not sworn to tell the truth, am I? Maybe so," he said in the midst of last month's recurring and rarely enlightening exchanges over the MX missiles.

He can be obscure: "Tentative decisions would imply the president has made some tentative decision," he said in another MX briefing.

But despite his idiosyncrasies, after five months as President Reagan's most active press spokesman Speakes has won the attention and the fickle hearts of many of his irascible listeners in the media.

"I've never known him to lie," said Bill Plante of CBS. "The thing I like about him," said Sam Donaldson of ABC, "is that he doesn't try to tell you the sun did not come up in the morning."

At almost 42, the sandy-haired and stocky Mississippian is enjoying the golden sun that bathes the pines and beaches of Santa Barbara and the whole early Reagan presidency. His team is winning, the economic program has passed, the nation's enemies are in some disarray, and Speakes is the first to admit that it is a nice change of pace.

He came to Washington to work as press secretary to Mississippi Sen. James O. Eastland in 1968, the same year he married his wife, Laura. As a young graduate of the University of Mississippi, Speakes had managed and then owned some small Mississippi weeklies, but decided to move on when a customer noted she "could throw our paper up in the air and read it before it hit the ground." In 1974 he moved to the White House, just in time for such dispiriting chores as handling press for Nixon's lawyer James St. Clair and, later, helping vice presidential candidate Bob Dole in the Republican's 1976 defeat.

After the election, Dole asked Speakes what he wanted to do. "I want to get out of politics," Speakes said. "I'm tired of getting beat."

He went to work in the Washington office of Hill & Knowlton, the giant public relations firm. But in the last days of the 1980 campaign he was back in politics, helping mostly former president Ford's activities for the Reagan campaign. Reagan won, and Speakes decided "I wanted to get back into government but I didn't have that connection. After a few days I finally got through to Jim Brady," who would eventually become Reagan's press secretary.

Speakes said, "Do you need any help?" Brady said, "We start at 7 in the morning, can you be here tomorrow?"

Speakes, who is listed as deputy press secretary even though Brady has been hospitalized since March, "hit it right off the bat" with his new boss. Brady, Speakes said, "had just no ego problem at all, he was a fun guy. We saw eye to eye on how to deal with the press." Since a bullet tore through Brady's brain in the attempt on President Reagan's life, Speakes has been acting as an energetic organizer of birthday parties and cards and letter campaigns to keep Brady's spirits up.

Brady's attitude, which Speakes says he shares, was "tell us what you need and we'll try to get it." It is a significant remark, for neither Brady nor Speakes was an insider and often they have had not much more firsthand knowledge of Reagan's thinking than the journalists they must brief.

During last week's continual MX queries, Speakes decided to say that some "preliminary" decisions had been made, since it seemed ridiculous to him to claim hours of presidential consideration of the issue had yielded nothing. He also announced he had misunderstood a previous guidance and that a projected 7 percent annual military budget increase was not a goal but only an upper limit.

Speakes has adroitly avoided defending any stories his listeners have known to be untrue, unlike his new superior, presidential communications assistant David Gergen, who tried to insist recently that U.S. ambassador to Saudi Arabia Robert Neumann had not been fired.

Instead Speakes employs a number of handy tools to avoid difficult questions. He can be abrupt: "Doesn't anybody have a question on a different subject?" he said when one reporter asked the 30th or 40th question on the Libyan fighter attack.

He can be angry: "Look. Let me tell you. I'm not going to sit here and argue and argue with you about a press conference," he said this week after some needling abuout the president's accessibility at his ranch. "You're going to have a press conference when the president is ready to have one."

Or Speakes can let ABC's Donaldson, who acts both as energetic interrogator and comic relief, interrupt at difficult points with a joke.

Reporter: "Larry, am I to understand the president was the last to know about the Libyan attack ?"

Speakes: "Well . . . . "

Donaldson: "No, I was the last to know, and some people are going to be fired at ABC ."

Speakes: "You surely were. I kept waiting for your call."

Speakes said he wants to return to newspaper work some day, perhaps following the lead of press office alumni like Tom Johnson of the Los Angeles Times or Gerald Warren of the San Diego Union.