Lou Harper's Blog
I think you're right; it's the sort of word her characters use. I use it in the family for fun, too, although I tend to use to to mean a snack. I also associate it with a chocolate-biscuit-with-fruit slab.
Her characters also "ejaculate" a lot. :P
New word for me.
It should be the name for a Dr. Who alien race. "The Invasion of the Tiffins."