Oh yeah. I haven't had time to set up my Wii and do anything since I got back from Hobo with work and life, so I'll just say it until I can get it recorded.
Basically, this came from Bigz telling me all the time to stop air-dodging into the ground. It's VERY situational, but if you're facing an opponent and going toward them, if you air-dodge into the ground, you can scoot backwards like a DR. Let's say you're facing to the right, then you can air-dodge so that the animation for it is still happening while you hit the ground. Point the control stick down and right before you hit the ground, and the second you land, rotate the control stick to the left (by going down right > down > down left > left), and if you do it right, Yoshi will slide backwards on landing.
I say it's very situational because you can only do it while facing forward while moving forward. If you're facing forward and you're moving backwards, then Yoshi will just run forward. If you are facing backwards and you're moving forward then Yoshi will run backwards. And if you're facing backwards and moving backwards, then Yoshi will roll. I haven't had time since I found it to play with it any more than just figuring out the button input and such, but it could be useful cause you can attack while you're sliding. Imagine landing near the edge of a platform, sliding backwards, and immediately attacking your opponent underneath said platform.
As I said in an earlier post, this has probably already been found out, but I haven't seen any Yoshi actually use it in a game, so it might be known but forgotten, so I might as well bring it up =)
Anyone wanna play around with it?