"Find out what they like, and how they like it/And Give it to them just that way," sang Roz Ryan and Celeste Annette last night at the National Theatre in one of the climatic moments of "Ain't Misbehavin'." This is supposed to be advice on how to hold a man, but the fast-moving song-and-dance revue demonstrated that the formula also works with theater audiences.

In two remarkably fast hours, the show moves from the rough-and-ready flavor of a rent party in "The Joint Is Jumpin'" through erotic idealism in "Honeysuckle Rose" and wild fantasy in "The Viper's Drag" to stark unexpected drama in "Black and Blue." The audiences went wild and can be expected to repeat its reaction through the sow's run, which ends July 27.

Everyone in the compact cast gets a turn in the spotlight during "Ain't Misbehavin'" and in this production everyone does the material justice. If one standout has to be picked, it would be Roz Ryan, a lady of generous endowments who knows exactly what to do with everything she has.But the real star is Fats Waller, whose music and style are what it is all about. If it takes five very talented singers and dancers, a good pianist and a six-man band to embody the spirit of this one man, that is a fair measure of Waller's dimensions.

The cast is completely different from both the one that opened on Broadway and recorded the RCA Victor Album, and the one that played here a year ago. But the music bends gracefully to the personalities of Ryan, Annette (who substituted for Loretta Bowers on opening night), Evan Bell (a slightly thin Waller Lookalike), and Lonnie McNeil (whose dreamy, rubber-legged "Viper's Drag" was as perfectly styled as his brisk brash "Ain't Nobody's Business If I Do"). Heaven, the brash young chick of the show, contrsts with the red-hot momma roles of Ryan and Annette. She dances with a special, angular kind of beauty and styles "Keepin' Out of Mischief Now" with a fine balance of seriousness and irony.

With "42nd Street," "Bubbling Brown Sugar" and now "Ain't Misbehavin'" playing simultaneously, Washington is currently nostalgia heaven for those who believe (as one of my friends does) that no good songs have been written since about 1949. Unlike the other two shows, "Ain't Misbehavin'" makes no attempt to set up a story line on which to string its song-and-dance numbers. The results is that each number becomes a mini-show in its own right: a tragicomic monologue by Bell in "Your Feet's Too Big"; a study of stylishness and the deep emotions it involves in "Lounging at the Waldorf"; an audience-participation show in "Fat and Greasy"; and a survey of World War II musical styles in "The Ladies Who Sing With the Band."

This final segment contains what looks like the least promising material and its therefore, in some ways, the greatest triumph of the show. Celeste Annette's "When the Nylons Bloom Again" is hilarious, but it is followed by something called "Cash for Your Trash," in which Roz Ryan manages to find heavy, raunchy overtones in a waretime drive to recycle waste material.

The tunes are among the best we have, the style is warm, funny, ribald and as nimble mentally as it is in the tunes and dances. That is to say, it is the style of Waller himself -- and that, too, is among the best we have. The show is reassuring evidence that we still have it.