Super Mario Galaxy 2 - Infinite flutter jump

Description
With this glitch, as long as you have Yoshi, you can go any place in a level, over a long period of time. This glitch can be frustrating to exploit, but once you master it, it is very, very useful. To perform this glitch, you first need Yoshi. Then, you start by performing a basic flutter jump. After that, you need to crouch (Z on the nun-chuck). Then, quickly release Z and flutter again. You can continue preforming this glitch until you mess up. If you do, you will fall either to your demise, or onto a planet or platform.

Why It Works
This glitch works because of the crouch. Crouching pushes you down slightly, and it is supposed to send you to the ground. But, due to the height of Yoshi's flutter jump, you can stay in the air after you crouch. The game thinks that you have landed on air, so it allows you to preform second, third, fourth, fifth, etc. flutter jumps.

Credit
MASTERLINKX

Trivia
This glitch is required to preform the erupting volcano glitch.