Hah!
I always equated it with corn sack.
I guess because, when I was a kid and we grew our own corn, we would always
bring it in from the garden in a paper sack and we would sit on the porch,
pull out an ear from a paper sack and shuck it.
hahahahahahah
Funny, I never gave it much thought, just put it in that catagory in my mind
without even asking myself why?

Matt