Archived Kimimaru4000 video from YouTube. Original description mostly intact:

This is a video of me flutter jumping to the lonely island with Yoshi. Since Yoshi can't swim, you'd normally need to jump on numerous boats that move across the waters of Isle Delfino to get there, or you can use a glitch that involves jumping through a building, which is faster. This method is probably the fastest method only if you can succeed on the first attempt. I hover backwards because Yoshi hovers faster backwards, and hovering forwards would take a very long time.

How to do this: After you jump with Yoshi, press X to dismount Yoshi and then press L right after to do a ground pound. Since you stop in mid-air when you ground pound, and since Yoshi stops in mid-air for a little bit after you dismount him, you go back onto him. This isn't as easy to do as it sounds because if you press L too early or too late, it won't work. You need to get it just right.

Enjoy!

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