On the Carrot Juice level in the Formerly A Prince chapter, go halfway through until you get to the first hidden Giant Red Gem. Smash it by shooting it with any gun, then go all the way to the right, where the bouncy thing is located. Do not go on it, or you will go up through the rocks and have to do it again. Continue right until you hit the wall, then run all the way to the left, where you first dropped down to get to the Giant Red Gem. It will be there again, and you can shoot it to get more gems. Go all the way to the right, then all the way to the left again. It should appear again. Repeat this to get as many gems as needed.