You need an area with multiple rotating blocks you can jump up to. We used the end of Yoshi's Island 2 to do this. In this level, jump three times under the blocks so that all three are rotating. Now, quickly run to the pipe at the left and jump from it onto the blocks. If the timing works out, the top two will still be rotating and you'll land on the bottom one which has finished rotating. When the top two blocks stop, they will try to push you out and the blocks will sometimes start rotating again if you manage to stay in your position among the rotating blocks.
Submitted by: kornyhatemachine