Some people perform this exercise with admirable calm, going under water, counting their seven counts, and then serenely opening their buckle and floating up to the admiration of their safety classmates.
Many others, like me, panic the minute they are underwater and subsequently find it almost impossible to undo their buckle. They then lose their direction completely and can't open their door. In the exercise, they are winched to the top of the pool by a burly man or two. In real life, they'd never make it out alive.
The terrible thing about this exercise is that you have to go under three times, and each time, for someone like me, it gets worse. On the last time I only just managed to stop myself from weeping in abject terror before being dunked. I got my certificate eventually, goodness knows how - all the while vowing to never set foot in a helicopter again unless I was unconscious and the helicopter had "Westpac Rescue" written on its side.
The reason this trauma springs to mind is that, for baby number three, I find myself in a somewhat similar position.
For the first birthing experience, few of us know exactly what to expect so while it is (usually) horrendous, it's almost as though you have a natural memory block that at least partially prevents you from remembering the full scale of the sheer agony.
My first experience of childbirth was unusual as well - I laboured and birthed without pain relief but only because no-one recognised I was in labour, and although the contractions were mind-bendingly painful, giving birth to a 1.4kg baby was far removed from the usual 3-4kg scenario.
The second birth, for many women, is quicker because they've already given birth and so apparently the body has a natural memory of the act and can push the baby out in a much more speedy fashion.
But for me, my second birth was like a first, as I was only six months pregnant when giving birth the first time around.
For my second birth, I needed two lots of gel to induce the baby as she was ten days overdue - and the labour went for about 20 hours.
Whether I'm traumatised from that ghastly experience or, like the helicopter safety exercise I know there's no getting out of it, I feel much more trepidation about this third and final birth.
Firstly, I'm worried that the baby will come so fast that I won't get to hospital on time (and either the kids will watch the whole thing in noisy horror or Ali, who blanches at the sight of a cut finger, will be forced to play midwife).
Secondly, I'm worried I won't have time to get any pain relief: I'm worried I will panic with the pain and I'm concerned that I will tear myself in two giving birth to what the obstetrician continues to call an "above average"-sized bub.
I know I should just "get on and do it" - after all, it's been my choice to have this final child so I can blasted well lump the painful bits.
My grandmothers had 14 babies between them without pain relief, and my mother had three of us (two of us twins) in a completely natural fashion, as was the way in the 70s in the back of beyond.
But, you know, I think it's important to acknowledge just how painful it is, and how scary it can be - especially when you know what you're in for.
All I would need now is to be caught somewhere remote and have to give birth on the rescue helicopter and I would either drop dead from all those phobias on top of one another, or come out a completely changed and emboldened person!
