30's, 40's phrase used on an uptempo dance tune, as a command to the rhythm section (the drummer is "daddy" as in "daddy-o") to emphasize 8 beats to every
bar of
music, giving it a feel of doubletime (as opposed to 4 to a
bar)
a command used by the
singer to go to doubletime, such as after a chorus, to
shout "beat me, daddy, eight to the
bar!"