In my Indigo Eady Paranormal Mystery series, I use something similar, only it's more like, 'Oh Crap!'.
That 'Oh Crap' moment is when my main character, Indigo Eady, realizes trouble is afoot. That both she and her gang of teenage paranormal investigators are in deep doo doo and the task ahead is not going to be easy. In fact, it's going to be hard.
I like to make it clear to my readers that doo doo is happening, so at the end of the first chapter in each book, when Indigo understands what the problem is, she actually exclaims,
"Oh crap!"
In Givin' Up The Ghost, it's that moment when Indigo realizes that her missing friend's father is a ghost, and therefore, not only dead, but murdered.
In A Guilty Ghost Surprised, it's when Indigo realizes that her little cousin has returned--from heaven.
While I use the term Oh crap! literally, it works like the thesis statement of an essay that directs the focus or point of the paper through to its final conclusion. It's a writing device that says, here's the problem, how are you going to solve it? When you write mysteries, that's what the book is about: how to solve the problem.
And of course, when you're writing for tweens and teens, words involving excrement of any kind is always good for a giggle.
I didn't consciously set out to employ the oh crap! writing device, but now I really enjoy using it.
What about you?
Do you use writing devices, either consciously or unconsciously?
What are they?