We don't spit, we emit lava
Pretty much saying that their lines are hot/fire cause lava= hot/fire.To emit means to give out/to issue. So they don’t spit. Instead they give us straight fire.
To help improve the meaning of these lyrics, visit “We Outta Here” by Joe Budden (Ft. Crooked I, Joell Ortiz & Royce Da 5'9") Lyrics and leave a comment on the lyrics box