Crawl-sliding is an SSBB technique which allows you to slide across the ground backwards for a short period of time. This was first discovered by Smashboards member lilscrappy561, who attempted to moonwalk as in SSBM by just walking instead of running. If done with a Bunny Hood, a character will slide even further, as if it wavedashed. This can only be done with characters that can crawl.
How To Perform
To do this, the player must tilt the control stick so the character will walk. Once s/he is walking, make a half circle in the opposite direction and let go of the analog stick. S/he will slide for a short distance unless s/he is wearing a Bunny Hood, in which s/he will go further. It is easiest to do this with Luigi.
Usefulness
With a Bunny Hood, if this is done, it could be quite useful. For example, if Bowser is behind Luigi, he could crawl-slide through Luigi and use an attack. If used correctly, Luigi could wave-slide and use his up-special and hit a character even though s/he is behind Luigi.