they whistle and stamp and some of 'em roar into the chorus of `` oh , you new york girls , ca n't you dance the polka '' and john thomas crosses his arms and starts in to dance , which causes his mates to cheer and shout , and so i starts into dancin ' , too , and that gets 'em cheerin ' louder , and so i goes faster and faster and i had forgotten how much i love this singin ' and dancin ' and showin ' off that i completely loses myself in it all , i love it so , and then john thomas crows out with , `` you ca n't match this step , girl ! ''