Heat the garlic and butter in a small saucepan over low heat for 5 minutes to infuse the butter with the flavor of garlic. Do not let the butter simmer. Stir together the sugar, salt, black pepper, and cumin in a small dish. Stir into the butter mixture along with the lime juice and hot sauce until evenly blended. Brush the ears of corn generously with the garlic butter; reserve remaining butter.