For many members of the state Senate, the irony was so delicious they couldn't tear themselves away. For years, they had watched their colleagues in the House of Delegates finish their business with alacrity, poke their heads in the Senate chamber, then head off--for home or the local bars--laughing at the Senate for holding interminable sessions.

But last Friday afternoon, the roles were reversed. As the Senate recessed at 5 p.m. after a week of peace, the House labored on, still distracted by the rancor-filled days of the immediate past and knowing a long Saturday session was still ahead.

"It was," said House Speaker Benjamin L. Cardin, "the toughest week I can remember since I became speaker."

The day that left nerves frayed throughout the House was last Wednesday. To put that seemingly endless day in perspective, one must go back to 11 a.m.--one hour into the session and more than 10 hours before adjournment. The topic on the floor was Gov. Harry Hughes' gasoline tax, one of the most controversial pieces of legislation on the 1982 calendar. Granted, the bill was not being considered for final passage. But its appearance on the floor was one of two chances for the del egates to take a public stand on it--to go on the record in opposition, to try to amend it.

But as the clerk called for the reading of the bill, the chamber may not even have had a quorum. The floor was nearly empty. The delegates' lounge at that moment resembled an airport on Christmas Eve. Delegates huddled in corners, sat on chair arms and passed newspapers back and forth.

Two names dominated conversation: Frederick C. Rummage and Robin Ficker.

Rummage (D-Prince George's), chairman of the Economic Matters Committee, had been grilled the previous evening during debate on the controversial interest rate bill his committee had brought to the floor.

While Rummage was questioned, committee Vice Chairman Casper Taylor had sat nearby holding a telephone. A Baltimore newspaper revealed the next day that Taylor had been talking on that phone to a group in the House Office Building that included the chief banking lobbyist in the state--feeding Rummage information and answers.

Delegates opposed to the bill called it disgraceful, since the banks had lobbied hard for passage of the new law. Delegates for the bill admitted it was embarrassing.

With debate on the interest rate bill, which would allow state-imposed ceilings on interest rates to rise from 18 percent to 24 percent on most consumer loans and credit card charges, scheduled to continue in the afternoon, delegates were far more interested in Rummmage's coaching than in the gas tax.

Then there was Ficker. The gadfly Republican from Montgomery County was being charged by the joint House/Senate Ethics Committee with possible violations of the state ethics law because he had solicited donations on a state-funded questionnaire.

Those two issues set the stage for nine of the most tumultuous hours seen on the House floor this term. From noon until 5, delegates argued, ranted and objected over amendments on the interest rate bill.

Cardin even gave up the the gavel for a while to Majority Leader Donald B. Robertson so that he could work the floor, finally collapsing into Robertson's seat for a brief rest.

"This is why I'll never run for the Senate," said Del. Robert Neall (R-Anne Arundel). "I couldn't take this for more than a day, if that long."

Many famished delegates sent aides to bring back sandwiches or hot dogs. Others smoked openly on the floor, a violation of House rules. Raymond E. Beck (R-Carroll), the minority leader, walked into the lounge, stripped off his jacket and did pushups to try to get the adrenaline flowing again.

The marathon debate on amendments to the interest rate bill finally ended at 5 o'clock and Cardin gave the members a brief respite until 6, then headed to the House Office Building because he was concerned that the votes to impanel the Ficker investigative committee might not be there.

"I had been told it might be close," he said. "I found out it wasn't going to be that bad."

Cardin was concerned because some delegates, aware that Ficker had been a thorn in the leadership's side for four years, were saying that leadership was out to nail him on a technicality. Not so, says Cardin. All he wanted, he said, was as quiet a resolution as possible.

It was not to be that way, however. As soon as the resolution was introduced many delegates, most notably Republican Luiz Simmons of Montgomery, Timothy F. Maloney (D-Prince George's) and David B. Shapiro (D-Baltimore), rose to defend Ficker. They attacked the ethics committee for leaking and Cochairman Sen. Julian L. Lapides (D-Baltimore) for derogatory comments made about Ficker during the investigation.

Finally at 9 p.m., a motion was made to end debate. The vote went up on the board, most delegates favoring the motion. Then Ficker, uncharacteristically quiet, stood and said, "Mr. Speaker, I would like the chance to explain myself before this vote is taken." Immediately, almost every delegate who had voted to end debate switched his vote.

Ficker had the floor for 20 minutes. Perhaps, some said later, he spoke too long. "Before he got up I was against the resolution," said Del. Frank Robey (D-Baltimore). "By the time he finished he had raised enough question I had to vote for it."

Finally, the House voted 73-47 in favor of allowing the committee to go forward with its investigation and the session was over. Many of the delegates canceled their plans to attend the legislative follies, the annual spoof of legislators by legislators, because they were drained and because they felt they already had seen enough folly to last a long time. A skit involving Ficker was removed from the show.

But there was one more bizarre incident to come. Late Friday afternoon, after the legislators had been accosted in the halls by anti-abortionists who kneeled to pray for pro-abortionists, they walked into the lounge to find a familiar figure: Gov. Harry Hughes.

Hughes had walked into the lounge shortly after 4 p.m. without any aides, trailed only by a lone plainclothesman. He poured himself a cup of coffee, spilling it in the process, and stood talking amicably with anyone who wandered by--delegates, reporters, pages. Each had the same question for the shy, often withdrawn, governor: "What are you doing here?" Hughes had a difficult answer for each.

"I'm just visiting friends."

"The elevator went the wrong way."

"I'm slumming."

Someone told Cardin that the governor was in the lounge. "Oh, that's okay," Cardin said without missing a beat. "He's a former member so he's allowed back there." Then he added, "I hope he's lobbying the gas tax; we could use a few votes."