"If President Reagan's public image has been dented lately, more than arms to Iran may be responsible. One explanation among the machismo set is that he missed out on his annual dose of "lamb fries" when he failed to attend Nevada Sen. Paul Laxalt's big Basque dinner at the George Town Club this spring.

Last week, acknowledging the strong ties of friendship he has with Laxalt, Reagan told retiring and defeated GOP senators at a farewell dinner that it is "no secret" how close they have been "these last six years, and long before. Paul, Nancy and I are grateful for all you've been to us."

Then in a provocative ad lib, Reagan said: "I've managed to stay his friend even having to eat those dishes at Paul's back-yard barbecues."

"Those dishes," as it turns out, are lamb testicles, which Laxalt, a descendant of Basque sheepherders, has flown in as the pie'ce de re'sistance of the dinner he throws for administration and Capitol Hill cronies.

Reagan never made it to this year's party, being otherwise occupied (bombing Libya), and in view of what has happened since, that may have been too bad for the president. The macho connoisseurs of lamb testicles believe that anybody who eats them can do anything.

All is not lost, however. Reagan has next year's dinner to look forward to, as Laxalt supposedly will join a Washington law firm after he leaves the Senate.

"When he was considering retiring from the Senate, Senator Laxalt told the president that he would remain in Washington for the balance of the president's term to help him out any way he can," according to a Laxalt aide.

The ways things have been going, Reagan may turn to Laxalt for help sooner rather than later. Laxalt's office already has been bombarded with media queries about whether he'll succeed George Shultz as secretary of state. Last week, yet another possibility drew a "no comment" -- that Laxalt might succeed Donald Regan as White House chief of staff.

" If the going really starts to get rough, Chief of Staff Regan can always run off to Florida, where he has just paid $ 489,500 for a country French- style four-bedroom home in the pine woods southeast of Sarasota. Regan reportedly wrapped up the deal two weeks ago as news of the secret arms sale to Iran was starting to break.

Regan and his wife Ann sold another home they owned on Florida's east coast. Their son, Venice, Fla., businessman Donald T. Regan Jr., said one reason his parents bought it was to be near family.

"Not only is Michael K. Deaver back in town, but yesterday he was having lunch at the Jockey Club with CBS White House correspondent Bill Plante.

"Mike feels fine and looks terrific," said Deaver aide Robert Higden.

Deaver was hospitalized out of town three weeks ago for an unex- plained illness. He currently is under investigation for his lobbying activ- ities after leaving the White House in 1985 as deputy chief of staff.

"Ever wonder who the high bidders are on auction items at charity fundraisers? The Fashion Group's recent tribute to Washington Post Fashion Editor Nina Hyde netted more than $ 200,000, of which about one-third was spent by designer Calvin Klein. His total outlay of $ 73,750 included not only a Herme's saddle (at $ 50,000) but also a tennis match with Art Buchwald and George Stevens Jr. ($ 1,500), a stay at Ralph Lauren's Colorado log cabin ($ 11,500), lunch with Bill Blass ($ 10,000) and a Raleighs $ 1,300 shopping spree (at $ 750).

Another apparent big spender was Bill Rubin, chairman of Bonwit Teller and president of Garfinckel's, who paid $ 2,000 for two Metropolitan Museum of Art gala dinner tickets valued at $ 1,500, $ 360 for a Kentucky horse-farm tour weekend and $ 750 for a shopping pig-out at Britches worth $ 1,000. Rubin's outlay for the Met tickets, however, was really just a short-term loan to Krizia's Aldo Pinto, who had only checks from his Italian bank with him.

Builder John Driggs paid $ 11,500 for the $ 6,700 "Magic of Milan" trip because he was bid up by Pinto and Carla Fendi, who really only wanted to have lunch with Georgio Armani. (Also included is a weekend at the Ferragamo family house in Florence, dinner with Tai and Rosita Missoni and two tickets to La Scala.)

Washington's own Huntington Block paid $ 2,000 for the $ 7,000 evening with cabaret star Michael Feinstein at the Ritz-Carlton's Terrace Room (and he has invited 80 friends to join him there for a holiday dinner, the price of which wasn't included in the evening with Feinstein).

David Narva spent $ 4,470 to have mom, the Jefferson Hotel's Managing Director Rose Narva, "cover shot" a' la Town and Country magazine by photographer Victor Skrebneski (whose fees for the rest of us would be $ 10,000 a portrait).

And jewelry designer Kenneth J. Lane bought the three-day getaway at Oscar de la Renta's Dominican Republic house for $ 2,000.

The list goes on and on and on.

"British sculptor Dame Elisabeth Frink got a look at her 1976 work, "Lying Down Horse," last week at the British Embassy, where it has com- manded a place in the garden ever since 1976, when Queen Elizabeth II came here for the Bicentennial.

British Ambassador Sir Antony Acland was out of town but in his absence Michael Barrett, who is cultural attache' and British Council representative, hosted a reception for Frink. Conveniently, she had only to walk across the street as she was the house guest of private collectors of her work, Leo A. Daly, head of an international architectural and engineering firm, and his wife Grega.

Among Frink's critically acclaimed works in the United States are "Eagle" at the John F. Kennedy Memorial in Dallas and "Fallen Birdman" at the Hirshhorn. What is not generally known is that there is another Frink sculpture, "Male Heads," in Washington. This one, however, is not on public view, although at times it is visible inside a window of former Iranian ambassador Ardeshir Zahedi's old residence on Massachusetts Avenue, which the Dalys rent from the State Department.

THIS, which stands for The Information and Hospitality Service, celebrated its 25th anniversary last week as best -- and sometimes only -- friend to thousands of foreign diplomats sent here since 1961. Notable by their absence were the group's inspirational leaders, beleaguered Secretary of State George Shultz and his wife Helena.

That, however, didn't keep the party from proceeding with vigor at the Willard Hotel, where manager J.T. Kuhlman, one of the original THIS young adults, cut the birthday cake. Not only did local volunteers and more than 500 diplomats from 58 countries show up, so did several of the group's original sponsors.

Among them were Jane Freeman, wife of John Kennedy's secretary of agriculture, Orville Freeman; Mary Louise Day, whose husband Ed was JFK's postmaster general; and Ethel Kennedy, whose husband, the late Robert F. Kennedy, was attorney general.

Kennedy and her daughter Courtney came from the annual Robert F. Kennedy Humanitarian Awards, where two Polish couples in the Solidarity movement were honored in absentia.

Some there were struck by the irony of the Kennedy women's introduction to a representative of the Polish government, embassy Second Secretary Wojciech Piatkowski, and his wife Barbara on the same day as the humanitarian awards presentation. Not Mary Louise Day.

"That is what THIS is all about," she said, "making friends with everyone."