Fluttershy moonlights as a masked pianist at a local nightclub to pay a few extra vet bills. Known only to the patrons as the beautiful and mysterious "Piano Mare", they lavish her with love and coin each time she comes. But one night Big Macintosh and Rainbow Dash are in the club at the bar, and they spot her. Will they see through the flimsy ribbon mask? (Song Fic based around Billy Joel's "Piano Man", Rated T for implied filly-fooling)