pedal stool

noun2

1. •
   A stool with vertical foot levers that attach to the pedals of a piano, organ, or similar instrument, thereby assisting children and other players who cannot reach the pedals normally.

   • A pedal-stool having an opening in its rear side to clear the piano-pedals. — 1904
2. •
   (nonstandard) malapropism of pedestal.

   • ‘I looked up to him, you know. I put him on a pedal stool.’ — 1993