From XxXArtemisXxX's suggestion that I try to explain what was going on in Luffy and Zoro's heads during that fight at Whiskey Peak. This is entirely speculation and never happened in the series. Tell me if this chapter is too confusing :(
Zoro knows it will never happen because he will not let it happen.
Yet there are things Zoro is willing to risk at the price of his arrogant pride and his crew members aren't one of them so after they leave Logue town, he finds Luffy. And he tells him about his katanas, and the new voice in his head when he grips the hilt of his cursed blade, the dangerous, soft lust that rings in his ears and Zoro tells Luffy no, never but at the same time he means maybe, someday.
Someday later, when Luffy comes yelling, accusing him of things they both know he would never do("They welcomed us with great food and you harmed them!"), Zoro is confused. When Luffy's fist comes flying and, for the slightest fraction of a second, his captain's gaze flickers to the crimson sheathed sword hanging by his waist, Zoro understands.