''It's just intuition,'' Mrs. Dukakis said, trying to explain her high spirits last week. ''It's something in the crowds.'' 'Something Is Happening'

One recent night in California, on his whistle-stop tour down the Central Valley, the Governor lingered at the end of his speech and let the cheers wash over him. He waved and smiled and waved some more, and still the cheers kept coming. Mr. Dukakis, a contained, controlled man, seemed overwhelmed. His eyes glistened. ''Something is happening,'' he told Paul Brountas, his friend and campaign chairman. ''We're moving.''

At the Queens rally, which was attended by such celebrities as Cher, Gregory Hines and Robert Klein, Mr. Dukakis accused Mr. Bush of taking a ''furlough from the truth'' when he adopted the ''I'm on your side'' slogan that has became the hallmark of the Dukakis campaign in recent weeks.

''Four days before the election, after all the slogans and the symbols and the advertising, four days before the election and he tells you he's on your side?'' Mr. Dukakis asserted. ''Who's he kidding?''

Mr. Dukakis went on to cite what has become ''exhibit A'' in his case gainst Mr. Bush: the Republican's proposal for a cut in the capital gains tax, which Mr. Dukakis saus is a gift to the rich. 'Picking Up Our Themes'

The Dukakis campaign sustained a combative mood throughout the day. John Sasso, the campaign's vice chairman, boasted to reporters today that the Vice President was ''picking up our themes.'' He also said the Bush campaign was placing new negative commercials on the air that involved the Massachusetts prison furlough issue and the Pledge of Allegiance.

One of the favorite Republican issues in this campaign has been Mr. Dukakis's 1977 veto of a law requiring the daily recitation of the pledge, after the state's highest court advised him that it was unconstitutional.