I gotta think of a plan so I can eat
I haven't had a cracker for weeks so my mouth leaks
His mouth is always drooling at the site of food. He needs to quickly think of a plan to escape the current conditions he is in.
Alternately, this cracker could be the use of that word as a pejorative for White people, indicating that he was not robbed a, presumably at least relatively wealthy, white person for so long that he doesn’t have enough money.
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