An extremely rheopectic sulfonate-based grease composition and method comprising adding overbased calcium sulfonate, overbased magnesium sulfonate, and a facilitating acid, using a particular type of overbased calcium sulfonate and/or methods for adding overbased calcium sulfonate relative to the magnesium sulfonate and facilitating acid to favor the reaction between the magnesium sulfonate and facilitating acid. A preferred overbased calcium sulfonate comprises benzene rings having multiple alkyl groups. Preferred methods comprise (1) adding all calcium sulfonate after adding the magnesium sulfonate and facilitating acid, (2) adding a first portion of calcium sulfonate with the magnesium sulfonate before adding the facilitating acid and a second portion of calcium sulfonate after the facilitating acid, and/or (3) one or more calcium sulfonate delay periods relative to adding the facilitating acid. The extremely rheopectic grease is fluid and pourable and only takes on a grease structure after milling or shearing.