The original meaning of the word Biscuit-eater comes from when a group of men masturbate together in a circle with a biscuit on the floor between them, whoever cums last on the biscuit then has to eat the biscuit.
Originally, a derogatory term for a dog too sorry to hunt anything but his own food. Can also be used for a person who is slow, lazy, or selfish.
An example, as from the movie it is based on (The Biscuit Eater), is a hunting dog that attacks the birds and eats them for himself instead of pointing or retrieving them.
A dog that is only half trusted. When it was common for people to put biscuits and pies on the windowsill to cool, a savvy dog might snatch them. A dog that, while polite enough while there's people in the room, will certainly stick his nose in the dip if there's no one in the room. Can also apply to two-faced, sneaky people.
A biscuit eater is a derogatory term for a dog too sorry to hunt anything but his own food. Can also be used for a person who is slow, lazy, or selfish.
Biscuit eater can be used in place of bitch in the phrase “son of a bitch” since both are terms for a dog.
Southerners use it as a way to cuss without using a curse word.