It's no backing down, it's 8 doobies to the face
Fuck that,

from Joey BADA$$ – UpDate Lyrics on Rap Genius

Meaning

Back/Face = Opposite

Joey don’t punk out now because your girl is about to face 8 blunts herself

The Line:

8 Doobies To The Face, Fuck That” — (Pronounced, “Fuck dot, just like K-Dot does)

Is from Kendrick Lamar’s Song A.D.H.D

http://www.youtube.com/watch?v=5MBz2tpAcEk

To help improve the meaning of these lyrics, visit “UpDate” by Joey BADA$$ Lyrics and leave a comment on the lyrics box