"Is it an earthquake or simply a shock? "Is it the good turtle soup or merely the mock? "Is it a cocktail -- this feeling of joy, "Or is what I feel the real McCoy?"

"At Long Last Love," by Cole Porter

Feb. 14, fast approaching, is the day to find out, but unfortunately there is no lover's litmus test. Man and maid, eager to know if it's at long last love, have devised countless rituals, from tossing an apple peel over a shoulder to reveal the initial of the lover to conjuring apparitions on Midsummer's Eve.

But inevitably, the rituals fail, and instead of trying to predict the future, we must settle for a moment's romance and decide how best to take heart on Valentine's Day.

A masked dance is a very romantic thing. People you know quite well will look mysterious and dashing when their eyes peer out from behind a mask. (Not, however, gorilla heads or Ronald Reagan rubber faces.) Even men who grow stubborn and irritable at the idea of putting on a costume will usually submit to a simple black mask. After all, the Lone Ranger wore one. And for women, there are elaborate sequined and feathered creations.

Ronna Costume Rentals, 1139 18th St. NW, has simple red satin ones for $2.95 or fantasy affairs shooting feathers in all directions for $29.95. Off the Cuff Limited Additions at 1077 Wisconsin Ave. has a mask edged in flashing, battery-operated lights for $4.75 (battery not included) and feather and sequined bird masks in a wide variety of colors for $35.

Dim the lights, push the furniture to the edge of the room, wax the floors to encourage the long, gliding steps of a waltz and buy all the Cole Porter albums you can find. Discover what a difference a disguise can make.

When people got too old for spin the bottle, or when they were embarrassed to suggest that instead of Trivial Pursuit it might be fun to have a rousing game of Post Office, they discovered fondue. Simple enough to prepare the pot of bubbling cheese, to pass out the long forks and the chunks of bread and to explain that anyone losing their bread in the cheese pot must pay the forfeit of a kiss. To one or to all, it is the host's prerogative to decide.

Many fondue recipes use cornstarch or flour as a thickener, and most suggest adding a dry white wine and a few tablespoons of kirsch. Not Brillat-Savarin, who favors a simple recipe that uses only eggs as a thickener (not to be overheated). Use a heavy pot and do not use pasteurized cheese, which never melts properly.

"Weigh the number of eggs you wish to use according to the presumed number of your guests. Then take a piece of good Gruye re cheese weighing one-third of this amount and a morsel of butter weighing one-sixth of it. You must break and beat the eggs in a casserole, after which you add the butter and the grated or minced cheese. Put the casserole on a lively fire and turn the contents until they have become properly thick and soft; add a little salt or none at all according to whether the cheese is old or not, and a good amount of pepper, which is one of the important characteristics of this time-honored dish."

And then swirl your bread around in the pot until it comes loose and you have to pay the forfeit.

Almost as much as the heart, Valentine's Day honors the sweet tooth, and many bakeries around town are selling special holiday desserts. Buy as many as you can for a sweets party, for heartburn instead of heartbreak.

The Bread Oven, 1220 19th St. and 1201 Pennsylvania Ave. NW., has individual heart-shaped strawberry tarts for $2.50. Sutton Place Gourmet, 3201 New Mexico Ave. NW and 10380 Old Georgetown Rd. in Bethesda, has heart-shaped cakes -- Grand Marnier and chocolate mousse -- as well as heart-shaped petit fours, chocolates and cookies, with the prices still to be decided.

The University Pastry Shop, 3234 Wisconsin Ave. NW, sells its heart-shaped cookies for $4.40 a dozen, and the heart-shaped cakes -- chocolate or yellow with mocha cream or ice-cream filling and red and white frosting -- are $11.50 for two layers, $17.50 for four. Suzanne's, 1735 Connecticut Ave. NW, has heart-shaped tarts, chocolate chestnut gateau and meringue shells filled with raspberry mousse at $3 each and heart-shaped cookies for 25 cents.

It's not only spin the bottle that got left behind in childhood, so did playing dress up. Gone are those winter afternoons spent teetering around the attic in mother's shoes, or flapping the arms of an old dinner jacket. But pantomime is a game that says it's all right for adults to pretend and on Valentine's Day what better subject than Famous Lovers?

Have your guests draw partners, and let each pair decide who it is they are going to be: Edward and Wallis, Abe'lard and He'loi se, Romeo and Juliet, Tristram and Isolde, Lillian Russell and Diamond Jim Brady. Then, each couple in turn, is given 15 minutes in the costume room to put together the proper outfits. (The costume room is any place with a mirror in it, stocked with all the bits and pieces you can find: old shawls and scarves, boxes of junk jewelry, abandoned jackets, and shirts and shoes, cardboard swords and paste tiaras, the things you would find in any respectable attic.)

Each couple, properly attired, mimes the lovers they are pretending to be, and the couple whose identity is guessed in the shortest length of time wins: a box of chocolates, one red rose, a book of love poems, a scroll guaranteeing that their love will last forever . . .