If you swive too swiftly, you'll get in a swivet.

This was a word that my Tennessee relatives used fairly often. My cousin commented that he really didn't hear it from other people.

As in sleepy? Curiously, I have found it to be defined 'dreamy' and 'extremely agitated'. And a variant spelling swevet. It's related to Latin sopor from the PIE root *swep-no- 'sleep, dream'.