This phrase should not be taken literal. This phrase is the English translation to the popular Spanish phrase, "comiendo mierda." It can mean someone who is lazy, not doing anything, or someone who is clueless.
Examples of How to Use the Word:
"Yo, Goey was eating shit all day yesterday. I told her to plan the getty, but she hasn't even picked up the liqour yet!"
"Bro, what is this chonga's life?! She was eating shit yesterday and almost hit my car!"
"F*ck MDC, they be eating shit bro -- I still having gotten my financial aid yet!"
By the way bro, stop eating shit and let's have a getty in the Latino Culture community. Dallleeeeee. ;) ;)