Fate has ordained this action.
Though the real reason that Oswald wants to slum it with Lube is thanks to Lube's big ass sheath. No one really talks about it since it's not given a lot of attention, after all, such private things should only be shared among close friends. But that's why Oswald is with Lube. They're very close, so close that sometimes they need something to help them get away from each other. Butt it's difficult you see, thanks to Lube's giant ass sheath, which while large enough to hold onto Oswald's weapons, also fit him snug and tightly, as if they were made for each other. Verily, truly two hunters forged by the passion of battle and friendship.