In case you can't WaveBounce, Reverse Aerial Rush to B-Reversed Aura Sphere can take its place, but anyways, always remember that in order to WaveBounce, you have to B-Reverse your Special attack which is easiest with Aura Sphere as Steam has said:
Button Input:
WaveBounce Left =
(Run right)
›(Jump while holding right)
› (Quickly flick analog left)
› +
(B-Reverse)
WaveBounce Right =
(Run left)
›(Jump while holding left)
› (Quickly flick analog right)
› +
(B-Reverse)
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When you set your C-stick to Specials, inputting a WaveBounce is easier & convenient, only having to press left or right on the C-stick.
WaveBounce Left =
(Run right)
›(Jump while holding right)
› (Specials diagonally towards the left)
WaveBounce Right =
(Run left)
›(Jump while holding left)
› (Specials diagonally towards the right)