If this sounds like something someone from Scotland might say when having to do a lot of boring busywork for some pernickety pest, well, yes. But it’s not an expletive. It’s a word for the tedious trivial tasks themselves, or, as a verb, for busying oneself about them. Here’s a citation:
Yet after a’, wi’ this fyke-fack an’ that fyke-fack, this thing an’ the tither thing, it cost me tippence or thretty pennies by the time I got without the port.