It's brown Chris Farley
I'm burly but surly, surely with a girl named Shirley
Heems is comparing himself to Chris Farley (RIP) by saying that he is heavier but at the same time menacing (unlike Farley). He finished up the line by saying that he was with a girl names Shirley, maybe this is a possible reference to Farley as he could have had a girlfriend sharing this name but it was most likely just to seal up the rhyme.
To help improve the meaning of these lyrics, visit "Girl Unit Wut Freestyle" by Das Racist Lyrics and leave a comment on the lyrics box