We've had half a dozen submissions in the past couple years that include phrases of the form "[person] slunk down in [possessive pronoun] chair." I assume that what's meant is "sunk down in" (I would say "sank down in," but sunk is an accepted alternate past tense of sink) but I find it interesting that the same misuse would come up repeatedly, in stories by a variety of different authors. I wonder if it's a common misuse in spoken English and I've just never noticed it.
(On the off chance that anyone reading this is confused, slunk is the past tense of slink; it implies motion from one place to another.)
In other news, I took a nap earlier for an hour or so. Doesn't actually make up for long-term lack of sleep, but helps some. Small triumphs.