I found the best place to earn this was during the challenge area on the second stage. Again, like before, you will need to earn gold medals on all the levels to unlock this challenge area.
Once you have the challenge area unlocked, bounce your shot to the end of the course and then detonate it just before it hits the towers at the end. This may take a few attempts, but it depends on which path you take and how early/late you detonate your shot.