In the interests of full disclosure, I’m writing this while wearing my third pair of trousers today.

By the time your second baby comes around, you’re pretty sure you’re unshockable. The first introduced you to diarrhoea so explosive it went up the walls, poo so gravity-defying it could somehow climb from the nappy up and out the neck of a sleepsuit, and vomit so pungent it melted the clothes from off your body. I’ve had piss on my nipples, shit on my neck and puke on my toes. The second child? A breeze.

And it has been. My four-month-old Rosie has been much easier, as far as that sort of thing goes, than her sister. She’s always snotty – my clothes are held together by snail-trails at the moment – but she isn’t particularly poopy or pukey. Indeed, other than a poo that jumped into my lap like a rocket-propelled sausage when I was changing her at about four weeks, she hasn’t grossed me out once.

And then today happened.

I was sitting on the sofa with my baby on my lap, happily cooing and gurgling and squawking to herself, as she does from half-five every morning. The Olympics was on the TV, my toddler was playing with a colouring book, and all of a sudden I noticed my testicles were getting incredibly warm.

Weird, I thought – my baby’s sitting on my thighs so it’s not her. But now my butthole is getting hot, too. It’s like I’m lowering myself into a lovely relaxing bath. What the hell is going on?

I lifted up my baby and discovered the awful truth – her sleepsuit was sopping wet. It was dripping down between my legs onto the sofa cushion, and then soaking up into my jeans and boxers. And yes, my nether regions were now swimming in baby piss.

It’s amazing how quickly urine goes cold. I stood up and as my boxer shorts tightened against my balls, I couldn’t keep a look of horror from crossing my face. You know the one – the look that comes over you when a pleasant, refreshing fart in a restaurant turns out to be something a little more than gas.

Screaming at the utter horribleness of it all, I handed the baby to my wife and hobbled upstairs looking like John Wayne after riding a stallion for twelve hours. Yuck, yuck, yuck.

Stripping off, I washed my junk in the sink, relieved to be free of the curse, and changed into fresh underwear and jeans. I went downstairs, to where my wife was changing the baby, and sat down on the sofa to watch.

Why does my butthole still feel wet, I wondered to myself. And then I realised I’d sat down in the puddle of urine still soaking into the cushion, and my newly-sterile groin was covered in baby pies again!

Poo from your face to your feet? No problem. Puke from my nipples to my nuts? Unpleasant, but I’ve got it in the bag. But white wine on my wedding tackle? You can get the hell out of my house.

I guess I’m still shockable after all.