I am at the age when women decide either to have one last baby who will be 5 to 15 years younger than the youngest child or to say goodbye to all that.

I thought I already had said goodbye to all that. After all, I had once gone skipping up and down the sidewalks shouting for joy over the last crib, the last high chair, the last diaper, the last trip where, before I could leave home, I had to pack a stroller, a bag with extra clothes, diapers, food, rubber pants, toys, pacifiers, bottles, formula.

I thought I had said goodbye in all those sadder ways, too: when I sent the first child off to kindergarten and the last child to the first day of all-day school. The first time I saw them removed from me on a stage, performing for me. The day I leaned over to kiss a teen-ager and, with a quick duck, the teen-ager removed the cheek and I was left kissing air.

But that was before I reached the age when goodbyes are forever. Now, when I look at babies and know I will never have another one, it makes me sad. But it frees me to think about babies in all the ways I was too busy or analytical to think about them before. Along with sex, chocolate, a hot bath and a good night's sleep, babies are the most sensual things around. To say goodbye to babies -- really goodbye -- is to acknowledge just how silly, vivid and ravishing it all was.

To begin with, babies have wonderful bodies. Their skin is smooth and undifferentiated. The bottoms of their feet feel like their cheeks which feel like their arms which feel like their silky backs. They are smooth and downy, inviting rubbing, caressing, long minutes in soothing strokes. Babies are rounded and firm; their flesh invites squeezing and kissing.

Babies smell good. All of them smells good -- their skin, their hair, their breath, which is sweet even when covered with mashed peas.

Babies are moist; little damp curls stick to their temples, to the backs of their necks. Their warmth makes their cheeks rosy, their bodies comforting. Babies never have cold hands.

Babies fit. They fit into laps pressing against us, within our arms so that our cheeks rest against their heads. They fit when they duck shyly away from strangers into our thighs. They fit when they get into bed with us and our bodies can curl almost completely around them as we all settle in for an extra time of comforting rest.

Babies also touch us. To a baby, our whole bodies are available. There is nowhere on us a baby can press and be intruding, improper. We women feel happy with our bodies, expansive and embracing, the way babies dive into us, hurl themselves against us seeking refuge and wherever they land -- against leg, breast or back -- they find succor.

Babies are wonderful to watch. They are droll, breathtaking, courageous, delighted, transparent. Their faces slowly pucker into outraged tears, slowly unfurl into tentative, tear-stained laughter. They turn wide-eyed faces toward us when the typewriter key they have just pressed makes a sudden noise and movement.

Babies allow us a last indulgence in the joys of simple fun. Like water. In the tub with wind-up toys that chug or dip through the waves, with a hose that provides delicious control over a wonderful, astonishing spray, in puddles, in the rain with an umbrella, babies coo and splash and balance themselves between the indignation of water in their eyes and rapture with their power over it. When we are the mothers of these water sprites, we get to play too, in water and snow, in sand and mud, in clay and finger paints, in dough and batter. Babies give us an excuse to get into goo.

Babies do wonderful things with their bodies. They fall smack on their seats when they lose their balance. They peer at us doubled over from between their legs with comic seriousness. They clamber over pillows and do effortless somersaults. They hoist themselves onto rocks, bookcases and rocking horses that are gigantic compared to their small size.

But mostly, babies laugh. Laughter is the gift children return to their parents for all the sleepless nights, the bone-aching exhaustion, the endless immersion in tasks so petty, so repetitive, so shut out from the great events of adult life outside our homes that sometimes we feel they'll finish us off physically and spiritually. And then, when we go in to get our babies from a nap they look at us with mischievous eyes from behind a blanket and we laugh and feel a rush of love absolutely physical in its intensity.

Most generously they allow us to make them laugh. To a baby we are unfailingly funny. Our jokes, our stories, our clowning find an immediate and gratifying audience. Babies laugh and giggle when we make a Bronx cheer into their tummy buttons, when we go mmmbbzzz into their necks, when we cover them with little smacking kisses. They smile at our songs; they clap and dance to our rhythms. They are delirious with the simple pleasures we invent for them: holding them up so they can switch the lights on and off and on and off.

Babies give us excuses for lazy days. Days when we play with stack-up toys for hours on end, building them up, knocking them down. When we make tents out of tables or bring all the cushions and pillows from the house into a central heap for tumbling.

I suppose that in caring for our babies we are babies again. We relive the freedom to laugh at something as simple as silly noises. We watch our babies' pleasures, always knowing we are watching them, always both within the experience and outside of it.

I suppose, too, this dual perspective allows the pleasure and defends against the pain of separation when it comes, helps us to turn to other things, to appreciate that for a while we have had the gift of our primitive selves restored to us to welcome and let go of when we have to.

And inexorably the leave-taking comes. We can thumb our noses at aging and defer the mourning with a last, late baby, but even that baby will grow up and the goodbyes will recommence: Goodbye to silliness, to damp hugs, to little bodies fitted against ours, gifts as fleeting as they are fine.

Linda Walker lives and writes in Ann Arbor, Mich.