There's a proper way to act at the event of the Virginia political season, and the friends of Joe Tolly are well aware of it.

As soon as they saw Tolly's white Cadillac nosing its way into the dirt-covered parking lot they ran over, thumped their fists on the car's hood and yelled at the top of their lungs, "Get out of the way."

This manner of greeting is quite in keeping with the fraternity-style atmosphere of the "shad planking," a yearly political rite that draws more than 4,000 to a small clearing in the woods about 3 1/2 hours southeast of Washington, near a tiny town called Wakefield.

The gathering, named for the fish that are cooked on planks of wood and served with a special sauce, is an excuse for anyone with a political interest to get out of the office for an afternoon and act a little "loose," as one participant put it.

The planking takes place in an area of the state with a worn-out feel and a history as a stronghold for Sen. Harry F. Byrd's Democratic organization. Closed gas stations, and small frame houses with their front doors propped open for a breath of air, dot the roads that lead to Wakefield. Pickup trucks are the popular vehicles.

Don Walsh of West Point started getting ready for the 37-year-old event at 10 a.m., "pouring bourbon from the big bottle to the little bottle." By 4:30 p.m. he, his brother Bob, and another friend, Bill Wills, were well into the spirit of the occasion.

They were waiting, for a reason that they were not quite sure of, by the six portable toilets, holding a drink for someone they didn't know.

"He just gave us his drink, left us to get in line and we haven't seen him since," said Wills. "That was 30 minutes ago."

Sen. Paul S. Trible (R-Va.) made a short speech, stressing that the new head of the Soviet government is "no choirboy." While a few participants responded with polite applause, many were not interested in serious thinking of that type.

The most serious speculation today seemed to revolve around whether it meant anything that Attorney General Gerald L. Baliles was sitting next to Gov. Charles S. Robb on the podium while Lt. Gov. Richard J. Davis was on the other side of the speaker, staring at the crowd with a preoccupied look.

Baliles has claimed that he has enough delegates to win the party's nomination for governor at the Democratic convention June 7.

Davis contends that some of Baliles' delegates were improperly elected, and is asking the party to unseat them. Robb is trying to mediate the dispute, saying that he wants to prevent "hand-grenade throwing."

Another subject of speculation was the absence of a campaign truck or posters for Rep. Stan Parris, the Northern Virginia congressman who is seeking the Republican nomination for governor. Parris's opponent, Wyatt B. Durrette, claims to have captured enough delegates for the nomination, but Parris is refusing to concede that race.

Democrats at the gathering tried hard to play down the bloodletting aspects of the Baliles-Davis struggle, while Durrette voiced obvious satisfaction.

"I like it," he said.

The event, restricted to white males until only a few years ago, drew more females and blacks this year than in the past, although they still were far outnumbered. It was Del. Mary Sue Terry's (D-Patrick) first such gathering, and it brought her at least one odd moment. A man asked her politely what campaign she was with.

"Well," replied Terry, who is the apparent Democratic nominee for attorney general, "I'm it."