I can't be sure exactly when my younger son Lucien's conversation took a decidedly scatological bent.

Perhaps it started when we were toilet training him last year, when every successful visit to the loo was applauded like a Genuinely Spectacular Event by us parents and his older brother.

Or perhaps it went a little further back, when he would overhear my helper and I discuss the kids' bowel movements - frequency, consistency, colour and smell - like diagnosticians pondering medical mysteries, whenever they fell ill or had an upset tummy.

The fact that I have a strangely-keen sense of smell - and am prone to yelling "Who farted?" whenever I catch a whiff of anything nasty - probably doesn't help. My impression of a bloodhound often sends the boys into gales of naughty laughter.

In recent weeks, Lucien has been talking dirty. Literally poop-and-pee dirty.

On delightful mornings, I would catch my preschooler in a bear hug and say: "I love you, my baby."

"I love you, shee shee," he would reply, deliberately and gleefully.

In the car, strapped in his safety seat, he would start on a bawdy chant: "My name is poot poot! My name is pang sai (Hokkien for 'to defaecate')!"

So sorry, if I am offending anyone's delicate sensibilities in print or ruining their appetite at breakfast!

The excrement talk got incrementally more outrageous. It was bizarre hearing my three-year-old talk like a fetish phone-sex line operator sometimes.

We tried to ignore him. Most parenting manuals advise that when young children use inappropriate language, it would be best to not overreact.

Otherwise, your shocked reaction might encourage them to keep using the lewd word, just to get your attention. The idea of saying a "bad" or a forbidden word can also be exciting to the child, who might then persist with it.

A fail-safe is to simply say, as calmly as you can, "we do not use this word in our family" - or something to that effect.

So, for a while, we ignored Lucien. Or, rather, the Supportive Spouse and I tried to - giving him a "stop it" glare, a warning "hey" or an irritated "tsk" when we could take the unremitting exclamations about various waste matter no more.

It got so bad that it was seriously embarrassing taking him to a restaurant. While polite people ate all around us, our son would shout things that he had no business shouting at the dining table.

Meanwhile, Lucien's seven-year-old brother couldn't help but be racked by laughter at his sibling's verbal diarrhoea.

Maybe, just maybe, boys have a section in their brain that compels them to find farts, boogers, stools and urine extremely funny.

Maybe there is an evolutionary function to such a pre-programmed neurological response, although I don't know what it is.

And - after reading American author Mary Roach's new book, Gulp: Adventures On The Alimentary Canal - I have to admit that our inner workings are as fascinating as they are gross.

In any case, we have finally hit upon a way to cure Lucien of his habit. These days, whenever he brings up rude bodily functions willy-nilly, we take him seriously and spirit him to the bathroom immediately.

The point we want to make is that it is okay to talk about pee and poo, because it is a fact of life, but there is a time and place for it. Keep the toilet humour in the toilet for now, buddy.

It seems to be working: He is less prone to yelling such things at random now.

Occasionally, I hear him catching himself before he utters a waste-related noun. Or he whispers it to himself so I can't be sure if I heard anything suspicious.

Still, I'm no party pooper. Should he and his brother feel the urge to giggle over the earthy evidence of our physical existence, they are welcome to go to the bathroom and get it out of their systems.

[email protected]

Get My Paper for more stories.