This is from the soundtrack to Black Snake Moan. Sam Jackson's character here was inspired by R. L. Burnside, who does a mean Stag hisownself. And he's backed by Burnside's own band here, as well.
But where Burnside was quietly laughing at the evil Stag does, here Sam Jackson boasts, loud and proud, of the violence and the psychopathy that the song brings out in him. Sam also curses a lot more too, but that's only to be expected. Nobody curses as well as Sam Jackson.