As I look at my hand, it's immediately clear that I haven't thought this through. I have a six-week-old baby balanced on one arm, my toddler is writhing hysterically in the arms of her equally fraught father, and now one of my fingers is tipped with poo. The wet wipes I so desperately need are lost somewhere deep in the chaos of the nappy bag at my feet, and as I juggle my baby and the offending finger, I wonder if this seven-hour night flight might just prove to be our last for some time.
Fatally, I'd recently turned my nose up at another mum who regularly used a finger to ascertain the exact nature of the nappy change required. "Why would anyone do that?" I'd asked a friend.
Now however, with the four of us squeezed into two economy class seats, sleep-deprived and hemmed-in by the in-flight bassinet, I appear to have sunk to an all-time low.
Usually a sniff is all it takes to review the situation, but the noxious whiffs emanating from my youngest defy easy classification. To top it all, my two-year-old has had only three hours sleep, and her screaming is visibly affecting the similarly desperate and exhausted passengers who surround us.
Biscuits and even mobile phones have been proffered, desperately, by way of distraction but nothing works. Our brains are pickled by exhaustion, and we lack that necessary parental magic - patience coupled with imagination - that usually makes all the difference.
What was my newborn doing while her sister threw an epic tantrum at having to sit still? The honest answer is that I cannot remember because, as ever, she was too busy being eclipsed by the more vocal demands of her elder sister. She probably slept soundly throughout.
I try to take solace from the thought that travelling with two children - necessary until they reject us as travelling companions - is not the hard part, and that it's travelling with a two-year-old that's the real killer. She won't always be two after all, and once I've managed to wash my hands, the thought comforts me.
On our next flight only a few weeks later I'm confident that I'm better prepared thanks to a portable library of sticker books and stories. Sleep the night before the flight is also in my arsenal.
Now when my eldest decides that nothing I've packed is nearly as interesting as everything else around her, I'm able to accept defeat more graciously and as my husband wanders the aisles, trying to contain her curiosity, I have time to reflect on my new strategy.
Far better, I think, in this situation to be left holding the sleeping baby.