This can be done pretty quickly by repeating the intro to Buttville. Collect as many blue orbs as you can while helicoptering.
Start by jumping left and grabbing back onto the starting platform - this will net you 4 extra orbs. Then jump off to the right and when you come to the Y, take the right path and then stay right in the open area with single spikes and finally take the left at the next Y. You can either restart here or continue for a short bit - I usually stopped at the third hornets nest.
Pause, select 'Restart Level' and repeat.