Spoken by southern farmers, and northern southern farmerwannabes, this term is used to show approval of something. It is a synonym for yes, or O.K. Also can be accompanied with a fake (or authentic) southern accent.
To heil oneself is to mimic this action that originates from the 2005 movie, "The Producers." The character portraying a very flamboyant Adolf Hitler lavishes praise upon himself when sings "Heil Myself."