Ainslie School year 2 student Taj Whitney-Nash helps author Andy Griffiths demonstrate what happens when you shrug your shoulders while making an evil laugh.

Ainslie School year 2 student Taj Whitney-Nash helps author Andy Griffiths demonstrate what happens when you shrug your shoulders while making an evil laugh. Photo: Jeffrey Chan

Were there any nightmares suffered by the little boys of the Ainslie School after, on Wednesday, famous children's author Andy Griffiths had asked each of them to imagine falling, naked, through a ceiling with a rubber duck in his hand and with a mouse-trap clamped to his penis?

And that wasn't all. With this columnist already writhing uneasily in his chair and with the eyes watering a little, the children and all of us were then asked to imagine things getting even worse! What if, their fabulously best-selling guest invited the boys among us to visualise, the ceiling they fell through was the ceiling of their sister's bedroom? And what if, more nightmarish still, it contained not only your despised sister but all of her girl friends, there for a sleepover?

The little boys in the room shrilled in horror.

Author Andy Griffiths explains the process of coming up with a story to students at the Ainslie School.

Author Andy Griffiths explains the process of coming up with a story to students at the Ainslie School. Photo: Jeffrey Chan

Or, almost as awful, Griffiths, continued, what if the ceiling you fell through landed you, naked remember, on your back on the dining table (here Griffiths did a realistic impression of a wriggling, naked, mousetrap-clamped boy on a dining table) with your parents entertaining some important guests, perhaps including the prime minister and the principal of the Ainslie School!? And at this point in this catastrophe, Griffiths asked his spellbound and whooping and cheering and shrieking audience of 300 primary schoolboys and schoolgirls, what would you do with the rubber duck? Yes, that was right, you'd use it to conceal that rude boy's bit of you.

Cursed with a vivid imagination (and so imagining myself falling, naked and mousetrapped, through the ceiling of The Lodge and on to Julia Gillard's dining table, perhaps during an official dinner for notable female heads of state like Germany's Angela Merkel and Argentina's President Cristina Fernandez) I didn't get nearly so much fun out of the rest of Griffiths' presentation as the children did. Griffiths, generally credited with being a godsend to the cause of keeping children reading books in these otherwise book-averse times, was at Ainslie School because in this National Year of Reading the children of the school had won the ACT chapter of a national competition designed to engage children in books and reading.

Griffiths is a National Year of Reading ambassador.

Ainslie School year 3 students Omar Algothmi, Benjamin Coram and Issac Jario get their books autographed by author Andy Griffiths following his visit to the school.

Ainslie School year 3 students Omar Algothmi, Benjamin Coram and Issac Jario get their books autographed by author Andy Griffiths following his visit to the school. Photo: Jeffrey Chan

''Each winning school won an author event,'' an assistant explained, ''and for Ainslie School, Andy is their prize!''

Yes, certainly the 300 children thought him a true prize. Lots of them arrived clutching copies of his books, all of them trilled with delight (and shrilled with ecstatic horror, at, for example, things like his story of eating his own poo when he was three and two blobs of it attacked him in his bath). During his performance and in his badinage with them, the children showed an amazing familiarity with his books.

Also on Wednesday, for this was also a book-signing and book-selling event, in a corner of the hall a trestle-table wheezed beneath the weight of piles of copies of Griffiths' books with such names as The Big Fat Cow That Goes Kapow, What Bumosaur Is That?, The Cat On The Mat Is Flat (the cover is a picture of a dazed cat that's been beaten flat with a baseball bat) and Zombie Bums From Uranus.

Author Andy Griffiths at the Ainslie School.

Author Andy Griffiths at the Ainslie School. Photo: Jeffrey Chan

The human bottom and its functions, a rib-tickling subject for today's children (just as it used to be for the English of the 1950s and 60s in the dreadful Carry On films) is a staple of Griffiths' oeuvre. His short biography in the front of one of his books informs that he lives in a former ''bumshelter'' (bombshelter, you see) in the city of ''Smellbourne.'' In Zombie Bums From Uranus the Zombie Bums of one planet have made their planet uninhabitable with their serial farting and the resulting, planet-crippling clouds of methane.

This columnist never recovered composure after the early-in-the-presentation story of Griffiths in the bath with his two brown blobs, followed up by the penis-in-the-jaws-of-a-mouse-trap-while-falling-through-the-ceiling scenario. His story about how funny it looked when his dog Sooty was run over by a car ''and all his guts came out of his mouth'' was a kind of last straw for this humourless dog lover (actually, not even the children seemed to get a buzz from this, and for once ambassador Griffiths may have misread his audience) and I left early.

As I left the hall, behind me it was ringing with the joy and laughter of the generation who are far better judges of the author's work and worth than this old curmudgeon. But I muttered to myself that at their age, me and my mates were somehow enthusiastic about reading, finding books like Robert Louis Stevenson's Treasure Island spellbinding even though no character in it, not even Long John Silver, ever farts or beats a cat flat with a baseball bat or gets his knob caught in a mousetrap.