It was the cartoon that finally got me.

I was sitting in an auditorium full of parents who, like me, were preparing to send a child off to college. I was on campus because my youngest son was attending an orientation program for incoming freshmen, but these days universities are savvy enough to know that offering a parallel "parent orientation" is a dandy way to get Mom and Dad on board with revenue-generating activities, from association fees to football games.

So while my son was learning the ins and outs of college life and choosing his classes for the fall, I was treated to seminars on everything from technology to how much bad dorm food I'll have to pay for each semester.

But the talks that received the most attention from parents were those involving the concept of "letting go." You're still the most important people in your students' lives, we were assiduously reassured, while also being told — in immaculately polite terms — that aside from keeping those tuition payments coming, we should now prepare to butt out.

At the end of one session, a cartoon appeared on the screen above the speaker's head. In the first frame, depicting "The First Day of Preschool," a mother tried to extricate herself from the vise-like grip of her little boy, who obviously did not want Mom to leave.

The second frame, with the caption "The First Day of College," showed a role-reversing scene of a teenage son attempting to flee from the embrace of his overwrought mother.

That's about when I felt the golf-ball-sized lump in my throat.

For the past several weeks, I've been engaged in a long, drawn-out process of letting go. First there was a spate of graduation celebrations and family gatherings, and as the summer wore on, the going-away parties began.

Wedged into the social whirlwind, we managed to fit in an exotic foreign trip. I had been blissfully happy when I first asked my son if he wanted to go and he registered surprise that I'd even felt the need to ask. "But we always go on family vacations," he replied.

And for a few short weeks, we indeed spent quality time together, learning about foreign cultures and customs, seeing strange and wonderful wildlife, experimenting with unfamiliar cuisine, and creating an unforgettable experience that time and distance can never rob from us. We were as close as we'd ever been.

Then, just after our return, the letting go began in earnest. We climbed aboard yet another plane on a journey to not-so-exotic Madison, Wis., where my son will soon be attending college. In just a few days, we had gone from tracking lions through the bush, to being back amid the surf and sand of Newport Beach and then traveling on to the land of cheese curds, cow tipping and cold, cold winters.

In a few weeks, we'll be back in Wisconsin again when my son is scheduled to move into his dorm and begin classes. This time, I'll be the only one with a round-trip ticket. It's going to be a long ride home.

Since returning from orientation, I've read and reread all the pamphlets and information packets that school officials showered upon parents. I figure the more I know about the school and the community, the more comfortable I'll feel about my boy living thousands of miles away.

I've also taken to heart all the advice proffered to parents in the materials provided. When the time comes, we're told, move-in day "is often one of the most emotion-filled days for both parents and students, and the tears may flow freely from everyone" — even from those parents who feel more relief than sadness.

But resist! we are urged. Resist the inclination to linger and arrange your kid's dorm room to your liking, fix any problems that arise, or call "just to check" as soon as you leave. And by all means don't use this parting moment to express doubt about whether your child has chosen well, or if he or she will be OK without you. "Know when it's time to say goodbye, and do it with love and a smile," we are told.

I'm certainly going to give it the old college try.

At the end of our family vacation, a few hours before we were to begin a long series of flights home, I watched my son strap on a harness hooked to a cable and step onto a tiny platform high above a magnificent gorge. We were just downstream from mighty waterfalls, one of seven natural wonders of the world. Below, the river water crashed into boulders the size of houses and churned in violent rapids.

As he stepped off the platform and accelerated to 90 miles per hour in near-vertical descent, I held my breath but did not look away. He raced across the gorge, then swung back and forth, and back again and again, finally coming to rest more than 100 feet above the foaming waters. Slowly, ever so slowly, he was hauled back to the top and the safety of land.

If there was a better metaphor, I'd be hard-pressed to find it. I let go and watched from afar as my son took a leap. I guess I'd better get used to doing that.

PATRICE APODACA is a former Newport-Mesa public school parent and former Los Angeles Times staff writer. She lives in Newport Beach.