I've tested this glitch on Mewtwo and Lucario
How to do it :
1) Jump
2) Neutral B
3) Shield
Repeat 2 and 3!
You can infinite wavedash in any direction
But dont do it when your almost to the blastzone
The only question I have is this.
Is this a glitch or technique?
Here it is in action
Is this broken like Brawl Meta Knight?