Whenever she was more than slightly outraged at her steady boyfriend - the one who had proven himself to be increasingly unsteady - my friend, Laura, would go out with a stand-by she referred to as The Dumb Blond. My friend's real name isn't Laura any more than the stand-by's name was The Dumb Blond. But I have found that the best way to keep your friends friendly is to lie about their names when you tell the truth about their sex lives.

The Dumb Blond was important to Laura for several reasons, not the least of which was that he kept her from going crazy over her unsteady boyfriend, who was smart and well-to-do and a neurosurgeon, and also (this happens with unhappy frequency is so many cases (equipped with yet another girl friend who was not Laura. The Dumb Blond was definitely not a neurosurgeon, which is always a help in any affair: and he also had, as they say, no visible means of support - which meant that a lot of their dates consisted of 1 a.m. beers at the neighborhood bar.

Finances aside, however, her friend excelled at several things, the mentionable one being that he was very good at being dumb.

"Sometimes we used to have their talks," Laura remembers with a shudder. "Well, we used to talk about the bomb, for instance. Yes, he used to say that the atom bomb would be really easy for him to make. That he could make one any time.

"And I would say, 'But what if some crazy terrorist or someone like that got a hold of your bomb?'

"And he'd say, Huh?'"

What we have here is not by any means an isolated incident. What we have here is a relatively new but rapidly spreading pastime. It is called Dating Down, and Washington, of course, has been doing it for years. Washington men, that is. The status of women has only recently been such that they could be doing it at all. So it is not easy for men to understand this phenomenon, despite and because of the fact that for centuries they have been the unconscious proponents of it.

"Man's love is of man's life a thing apart/'Tis woman's whole existence," wrote the smug Lord Byron, who doubtless would have liked to have kept things that way.

But, as Don Juan possibly figured out, it really takes a lot out of a person, being in love. You have to think about that person. Then you have to thing about what might do when you're around. Then you have to think about what that person might do when you're not around.

These are thoughts inimical to huge productivity, job security, and promotions. What, after all, did Lord Byron know about working women in our nation's capital? What did he know about the needs of a neurosugeon's girl friend? What did he have to say about such lines as "You're a liberated woman; you move your own furniture"? Or, worse; "You're a liberated woman. Why do you keep thumbing through my address book?"

Dating down ensures three things: no jealousy, no wearisome searches for the man's identity, and a lot of moved furniture. Men who date up so often perform these little services by way of demonstrating their gratitude.

Men who date up, also quite often, have no identity to search for - really, rather a considerate omission on their part, and one that has saved many a lady a tedious voyage into the swamps of boredom.

"I'm just trying to find out who I am," a sputtering flame once told me, by way of explaining his foul moods. Since he was a drama student, he was allowed these little excesses of rotten temperament, which I was not. Since he was a drama student, I decided to help him discover who he was, a process that took over four months, and which ended the night he starred in King Lear. Then we both found out who he was.

He was a dreadful actor.

Instantly I realized I had been dating down. Automatically his moods improved. When I left school, he helped me move my belongings and proved he was also a bad writer in his regular correspondence. I, in turn, became engaged to someone else.

It's as another friend, a writer, says, "I have dated down - sure. Because there's no danger in getting involved."

Yes, it's guaranteed no-hassle. And can we honestly say as much for any other labor-saving device?

Women can date down in any one of three ways: If he is less intelligent or less educated than she. If he earns or has far less money than she. If he is a good deal younger than she.

You will notice that the last instance, when reversed - when applied to a man with a much younger woman - confers no diminution of status on the man at all. Confers, in fact a certain cachet on the male who becomes the object of great envy and admiration among all his fellows. Which brings me to my point.

Men cannot date down.

Or to be more precise, a man can date down, but is never preceived to be doing so, which is all that counts. If he goes out with a lady considerably dumber than he, it is founrly assumed he is performing a valuable service, and will ultimately Teach Her To Know Better. If she is earning less than he, that is considered simply a manifestation of her good breeding (at least she isn't pushy) and his good taste.

In fact, the only way a man can date down is by dating up.

"He is aware he's dating up," sighs a compassionate friend of a man in this unfortunate precdicament. "And he's getting so insecure."

The friend shakes her head sympathetically. "He keeps telling everyone how lucky he is. But he's really nerous she'll leave him. And she will, too. I mean she's moving back to New York, and I just know - it'll break off. I know her mother's going to fix her up with this hot-shot lawyer. And that'll be the end of it. Now that she's moving away, he's really besides himself."

Men know. They have seen the future and it's no longer entirely theirs. Men understand only too well the desperate plight of other men, rendered nervous by their association with mobile and upwardly mobile ladies. To undermine the increasing inevitability of these associations, they have plunged into one of two choices. Some have of course run for solace to extravegantly stupid women - but of these there is a rapidly diminishing supply, owing to increased demand, heightened consciousness, and a general tendency towards obfuscating one's defects.

Others - and these are by far the majority of tortured men - have chosen for themselves some special field - any field really - in which they evince an interest at obsessive it excluses their partners.

Most men these days tend to launch relationships with a detailed account of their specialized interests. They will inform you of their lifetime subscription to "Warship Montly," a magazine which, as its name implies, features luscious photographs of nude battleships. They will tell you of their vain but determined efforts to mate puppies with killer-whales in captivity. Only the grossly naive will assume from this that they want you to share in these passions. In fact, they want their women friends to remain in steadfast ignorance of these areas. There are, after all, so few remaining areas in which they can excel alone.

I have a friend, for instance, whom we shall call Lloyd is a gourmet cook. Lloyd dates women who can, with a certain amount of difficulty, pop a Celeste frozen pizza into the oven, and this is no accident. Lloyd likes to Teach Women To know Better.

Like any self-respecting gourmet, Lloyd owns a $225 food-processor called a Cuisinart that chops, minces, whips, and performs in general with food like the Marquis de Sade performed with women.

For Christmas Lloyd gave his lady friend a food processor - the Farberware model that he got for a 100 bucks on sale.

He got away with it.

No doubt a lot of you are asking yourselves why smart, ambitious women these days are dating down. Why do they expose themselves to inferior intellects, smaller pocketbooks and men who claim they can manufacture atom bombs, when we are all supposed to be searching for compatibility?

The answer is relatively simply Smart women are tired. All day long they compete, they achieve, they battle. Choosing a smart man will entitle them to do these things all night along as well, and also to listen to such instructive lines as "why do you always have to be right?" Like sex with which dating down has a lot in common and even more to do, stopping to conquer entitles a lady to a good night's rest.

"The only problem," sighs a lady who had done it, herself, "is that it ends. It's bound to end. It's just a respite. And I always feel uncomfortable about it. Not compromising - but I feel, you know, that I can do a lot better. It gets so boring."

Which brings us back to the saga of Laura and the Dumb Blond. He was very good for her. She ended up marrying the neurosurgeon.

When the time came, she called, as civilized women must, to explain the evolving circumstances to the Dumb Blond.

"I'm getting married" she told him.

"Oh," he said. There was a long pause than we will retain from calling pregnant. Then: "Does this mean we won't be able to see each other any more?"