My husband was horrified when he heard me sing this to our little one so I thought I should do some research! My grandmother used to sing to us:

Now it's time for piccaninies all to go to bye byes
rest your little weary head and sleep
otherwise the sandman will come and get you children it's time all little coons were fast asleep

Go to sleep, my little piccaninny
Brer fox'll catch you if you don't don't don't
Slumber on the bosom of your ol' mama jinny
brer fox'll catch you if you don't