My grandmother use to sing it like that to me.

Go to sleep my little pickininny
Bryer fox'll get you if you dont
slumber on the bosom of your 'ol mammy Jinny
Im a gonna swat you if ya dont

chocarooo chocharooo chocharooo aroo aroo chocharoo

or something like that.
Im from Pennsylvania. Her parents were Irish. So i have no clue where she got it from.