First do the Debug code and go to any stage and turn Tails into Super tails. Now press B and press A until you become an enemy. Keep on making enemies on Super Tails. You'll start to get lots of lives while Super Tails destroys the enemies you create.

Note: If you have a controller that can either let you have things go slow, turbo and normal, you can change it to turbo and hold on to C and you won't have to keep on pressing the C button.