"Hair of the Dog" is the title track of Nazareth's 1975 album Hair of the Dog. It is sometimes called "Son of a Bitch" because of the repeated lyric in the hook ("Now you're messing with a son of a bitch"). This song is about a charming and manipulative woman who can get guys to acquiese to her every need. The singer is letting her know that she has met her match in him, and she won't be able to push him around.
"Hair of the Dog" uses a talk box extensively during its bridge. The song's title does not appear in the lyrics, but is based on the expression. The logical title would be "Son Of A Bitch," but it would be tough to get airplay with such a vulgar title. The title is a pun, as "heir of the dog" refers to "son of a bitch".
^Strong, Martin Charles; John Peel (2004). The great rock discography. Canongate. p. 1064. ISBN978-1-84195-615-2.
^Brewster, David M. (2003). Introduction to guitar tone & effects: an essential manual for getting the best sounds from electric guitars, amplifiers, effect pedals, and digital processors. Hal Leonard Corporation. p. 60. ISBN978-0-634-06046-5.