FOR THE PAST year I've been taking my two children to the playground almost every day it isn't too cold and the sun shines. I march them in with a Fisher-Price dump truck, a dimestore tow truck and parts enough for two from various pail-and-shovel sets. I plant them in the sandbox and go sit on the bench with the other mothers.

At first it was unsettling, because actually I'm a father. I've since become a regular, regognized as such. At the grocery store I say hello to women I know only as Rachel's mother or to the mother whose kid's plastic motorcycle Benjamin always rides.

That's part of the etiquette. A woman I've talked to frequently was at the playground one day with her husband. Our children ended up together on the merry-go-round. She started to introduce her husband and had to stop. She didn't know my name.I didn't know hers. I said my name and he said his. He stuck out his hand. I shook it. It was the first hand I'd shaken at the playground. I still don't know her first name.

There's a protocol about toys, too. People who've never been before, especially fathers on the weekends, either bring no toys and run themselves ragged making their children put down the toys they pick up, or they bring toys, usually too many, and spend their time coaxing their children to play with their own things.

Regulars bring toys at the rate of one, maybe two, per child. Toys are like tickets of admission. Kids will play with their own toys. Or kids would just as soon play with somebody else's. Regulars make note of the toys our kids like, with an eye toward the next birthday. At the same time we're alert. Whatever children are playing with, it's theirs, to be held on to with the dour tenacity of the defense attorney in an antitrust case.

When the inevitable confrontation occurs, we watch. We turn away if an adult has to intervene. When a child gives up a toy voluntarily, we are pleased. When a child gives up a toy without trading for it, we remark on the child. When a child gives up a toy that is the child's own, without coercion or anything offered in return, that child has shared and we regard the act as a triumph of civilization, which it is. Even when the child immediately runs off to slide.

This talk of toys defines our playground as upper middle class; relatively well-off people use it. Foreign women, the wives of diplomats, appear frequently. Others, as they have told me, are Foreign Service wives.

For a time, I felt awkward at the playground. I was raised in South Carolina and Georgia. Until I went to kindergarten, I played in backyards. Every house on the street had children. Every mother stayed home. Playgrounds were, to me, an exotic, urban locale.

A woman I know, Egyptian-born and French-educated, remembers that when her husband was in the Army, she thought she had the only pram in the little Alabama town where they were stationed. She walked her baby every day. The natives said outright they found it strange. Americans, she thinks, don't take their children out enough.

Another woman, who works, told me she grew up in a little Michan town and never thought of parks as places you went to every day. She said she was surprised at the determination of an English baby sitter she once hired to get to the playground twice a day.

I know what they mean. Almost every pretty spring afternoon I was there, a Frenchwoman walked her mother to the playground. They sat on a bench and watched the children play. I have seen no one else do that.

My wife is an airline reservations supervisor and I am a writer. Before our son was born in the fall of 1975, she went to work every day and I had the house to myself. After her maternity leave expired, I wrote during his morning nap. After our daughter was born in the fall of 1976, it still made sense, financially, for my wife to go back to work.I wrote less and less. I was spending nine or ten hours a day alone with the children. It was driving me crazy. I started taking them to the playground.

I went at different times of day, depending on my wife's shift. Because I didn't seem to be there every day, the regulars used to ask about my absence. Once a woman said she thought the men had abandoned them again. A friend in another city, a schoolteacher who gets home before other men in his neighborhood, told me the same thing happens to him. When he takes his children to the playground, the women say they like to have men there.

At whatever time of day, it's impossible to think consecutively at the playground. It's also impossible at home. That has been the biggest shock of my parenthood - the frazzle which mothers of small children experience. My wife has a lot to tell me when she comes home. I don't have much to tell her. What I was thinking about that morning, when I sneaked off from the a.m. "Sesame Street" for a private cup of coffee, is a jumble. Something cute happened at the playground and I can't remember it.

She tells me about an incident at the office, I start to reply, and our son insists that she look at the steam engine he's drawn. She admires it. I'm glad it's not my attention he's demanded. Thinking that, I lose my train of thought. What were you saying?, she asks. Nothing, I answer. You're not interested? she asks. It's not that, I say.

At the playground I talked about that. I now converse easily with housewives. One night, at dinner with friends, a woman and I kvetched to each other about how ungraciously our spouses receive midday phone calls. And never call home. They don't understand the sheer need to talk to an adult, we agreed. She told me that her husband's companystarted monitoring outcalls as an index of productivity.They told her husband he was making too few. Then, she said, he began to call home.

That's a war story from the other side. I like war stories. A year ago, I would have enjoyed Alfred Kazin's tale of the Wednesdays and Sundays his divorced wife gave their son over to him. "And you entertain him," Kazin wrote in "New York Jew," "sitting with wildly bored and distracted women looking you through and through and making amazing conversation with you, the only man in the playground at 2:30 in the afternoon."

A year ago, that's something I might have said. Now it strikes me as superficial, condescending. It can be boring to mind children. If children enjoy burying a toy in the sand, they'll enjoy doing it 27 times in a row. Some days I've pushed a swing until it seemed that, if there ever was a time I had not been pushing a swing, memory runneth not to the contrary.

Kazin was right in saying these women were distracted, but around children adults always exist in a state of distraction. That's part of the job.

In "Silences," writing from a depth of understanding that astonishes me, Tillie Olsen said "Children need one now (and remember, in our society, the family must often try to be the center for love and health the outside world is not.) The very fact that these are real needs, that one feels them as one's own (love, not duty); that there is no one else responsible for these needs, gives them primacy. It is distraction, not meditation, that becomes habitual; interruption not continuity; spasmodic, not constant toil."

This is apparently why people object to a life that leads to the playground. In Anne Richardson Roiphe's "Up The Sandbox!" the wife says her husband thinks "I'll grow stupid and dull if I just sit in this playground day after day. I suppose he's right - nothing really happens - nothing challenges wit or demands a fine performance."

No, nothing does. In late afternoon, when working mothers come to the playground to collect children from play groups and baby sitters their well-cut business suits and bright neck cloths and touches of jewelry shout of a perfection beyond our reach. But they can't walk into the sandbox because of their shoes, which this year are a ridiculous five inches high (a sexual zero-sum game: the two inches lopped off the edges of men's ties have been tacked onto the heels of women's shoes.)

Life at the playground is compromise, retrear. This changeable spring there has been much concern with temperature. The other day a woman called out, "Brian, aren't you cool? Don't you want to put on your jacket?" Brian did not want to. "Brian, why don't you move into the sunshine? There's just as much sand in the sunshine." Brian didn't move. She let it go. They would be leaving soon.

In the long run this could be debilitating. Perhaps Tillie Olsen is correct in looking back bitterly on her not writing in spite of an urgent need to during the 20 years she raised her family. She concluded: "Work interrupted, deferred, relinquished, makes blockage - at best, lesser accomplishment. Unused capacities atrophy, cease to be."

I hope she is wrong, but I have have to admit that it takes an act of faith to carry on, in spite of the evidence that she's right. I used to be able to write early in the mornings. Then my daughter started getting up with mw and insisting on helping me type. For the moment, I'm not writing much at all. If I can build an office in the basement soon, and find a baby sitter. I see mothers at the playground struggling with the same dilemma. A nurse who used to come to the playground took weekend shifts at a hospital. A librarian works part-time for a university research project. The rest, I've heard talking about what they will do what they will do when the last child is in school.

But it is oppressive to realize that caring for your own children is scorned as unprofessional. There's not future in it; we all know how awful career mothers are. Worse, it's unpaid. Caroline Bird, who writes about working women, has said, "The cold fact is that work is done better when it's done for money."

Cold, all right. I'm not sure it's a fact, not at the playground. I've watched the baby sitters. They're competent. They care. They're not parents.

In this walkaway society we discard husbands, wives, jobs, home towns. We asphyxiate pets at the animal shelter. But we can't get rid of children - at least women can't, at least not yet.

That, for me, is the irreducible fact of the playground. The women I see there are attached to their children and the connection is voluntary and, from all appearances, permanent. It is also inexorable, as I am beginning to know.

And I'm beginning to see that it wouldn't hurt other men to paint themselves into the same corner. CAPTION: Picture, no caption, By Margaret Thomas-The Washington Post