Manure = shit.
Unlike, THISLIFEILEAD, I don't think it means he is 'fucking hoes to shit'.
It means he is playing them like they're shit - treating them like they're worthless.
As for being original, I don't think it had anything to do with this. 'Manure' is simply used for rhymes' sake &, if there is another reason, to break the monotony of saying 'shit...shit...shit...shit'.