Butterfly on the ground / floor
 

hi
some (experienced) duellers will know this: the butterfly, where you don't leave the ground, but slide across the floor while performing a butterfly.
this attack is, however, extremely effective, cuz it's hard to be noticed as bf early enough.
my question is: what is the safest and easiest way to perform it?
I have heard different versions, but it only works in a few lucky cases.

You can do a butterfly off a platform or higher ground and when you should be doing the jumping, you'll be in the air. That's the only one I know of and it works all the time for me.