This phrase is used to either be emo or to mock an emo kid. It describes the classic emo musician and poignantly mocks the ever-so-sad emo song.
A: I ran out of black eyeliner this morning, and my new hair isn't as black as I wanted it.
B: This is such a cruel world...
Bystander: Aw, I'm gonna tune my guitar to sad.
by Lia M. April 15, 2006
Get the Tune my guitar to sad mug.