Yes, here we have a childish image. It works so we use it, ha. Step back into the mind of your 5 year old self and imagine every group of two black keys on the piano as a little dog house. Practice going directly to each D on the piano, playing at various volumes -- loudly or softly. Use either your 2nd or 3rd finger to do this so that your hand will stay in proper position. Draw beautiful arcs with your hand when moving from one D to the next.
