"Noah, are you doing a wee?" I ask, in that kind of worried tone parents have when they know their peace is about to be shattered.
"No," he replies. The growing dark patch seeping through the denim of his jeans and down his inner thighs, though, reveals the truth.
Exasperated, I yank his trousers and pants down; but it's too late. I've shut the stable door after the horse has bolted, except in this instance 'shutting the stable door' means pulling down his underwear and 'the horse has bolted' means he has peed all over himself and the carpet.
Potty training is - along with playgroups - one of the many scourges of parenting. Noah knows what he is supposed to do, and knows what the bright blue potty is for, but after a week or so of potty training we're still coming up against frequent accidents.
We turn to books, of course, but - as we've found previously - they're not that much help. It's all theory, and you shouldn't do this, and should do that, but what the authors don't account for is that sometimes you might be in the middle of Sainsbury's holding a baby in one arm and a trolley in the other when your infant decides that now would be a good time to soil himself.
Many people say that we should wait until he is ready, which - again - is great in theory, but they don't know Noah. This is the child who learned all his colours and then - for reasons known only to himself - decided to forget them all again.
This is the child who calls us to retrieve a teddy bear he has dropped out of bed instead of just leaning down and picking it up. Essentially, what I'm trying to say is that Noah is lazy, and if there's any way he can go a few more years without having to learn to go on the toilet, he will.
Couple this with two other factors which feature heavily in any parent's life: money and competition. Times are hard, of course, and nappies are expensive. Really expensive. (Before you say it, we tried reusable nappies with our eldest son, but it didn't work out.) We can't afford to keep spending fistfuls of cash on nappies when there is the chance that Noah could be rid of them altogether in a couple of weeks.
And then there's the competition element, the other parents with children of a similar age who brag smugly that their little cherub has been dry for five nights in a row.
But if there's one thing I've learned so far during the six years I've been a father (and you'd hope I'd have learned something), it's that what other parents say isn't always true.
Next time a boastful father or mother tells you that their child is potty trained, have a quick look at their kid's trousers. I'd like to wager that they'll, too, be sporting a growing wet patch, proving that - sometimes - it's not just kids who tell the fibs.
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