M-style stands for Monk-Style. It IS a subdivision or demonination of K-style. Monk-style focuses SOLEY on the use of the Sword. It came around when someone named "Monk" used a MRB to be able to get 3~5 slashes in just one jump, aswell as being able to block a lawnmower hack by about 80~85%.
Without a mouse rebinder I doubt that it's possible since I have never tried this out for myself.