Hi guys, I'm DeLux and I write smash tutorials.
The "double B reversal" you are asking about is what is called "wavebouncing" or less often a "recoil special".
In order to do this, you have to combine both methods of turning around a special option. The two methods are:
Turn around special: Where one makes an analog stick input in the direction opposite of which they are facing before they input special button.
For example:
Analog back tap and release > Special button = Turn around Neutral special
Analog back tap and hold > Special button = Turn around Side Special
Analog back tap and/or hold down in reverse direction > down + special button = Turn around Down Special
Analog back tap and/or hold Up in reverse direction > Up + special Button = Turn around Up Special
The secondary method of turning around while performing a special is a "Reversal". This causes a player's momentum to shift in the completely opposite direction while turning around and performing the option.
For example:
Special button > Tap analog stick back = Neutral Special Reversal
Tap and/or hold analog stick in direction you are facing > Special Button > Tap Analog Stick Back = Side Special Reversal
Tap and/or hold analog stick in direction you are facing with down orientation > Special Button > Tap analog stick back = Down Special Reversal
Tap and/or hold analog stick in direction you are facing with up orientation > Special Button > Tap analog stick back = Up Special Reversal
It is important to note that the direction you tap the analog stick does not equal the direction your character will move and will is more inline with the direction they will face. It is not uncommon with a reversal to tap the control stick left only to have your character to reverse momentum to the right, especially if you were drifting backwards in compared to the direction your character was facing originally.
So in order to do the wavebounce, you combine the two:
Gently move control stick in reverse direction > Special input > tap control stick forward = Neutral Special Wave Bounce
Tap control stick back and hold > Special input > tap control stick forward = Side Special Wave Bounce
Tap control stick back and hold in downward orientation > Special input > tap control stick forward = Down Special Wave Bounce
Tap control stick back and hold in upward orientation > Special Input > Tap control stick forward = Up Special Wave Bounce
Remember, the reversal aspect of the special option is what causes the bounce back as it reverses momentum. So in order to bounce backwards, you want to retain as much of your forward momentum as possible with precise and efficient inputs prior to hitting special. Similarly, if you drift away while facing from someone, you can use the wave bounce to launch yourself back towards them. But in effect, the turn around special aspect makes you face backwards, and then the reversal aspect makes you turn around yet again (while shifting momentum) making you face the original direction.
I know this is a stupid question lol.
How do i do a standing grab in the opposit direction. I know how to do it when running but not when standing.
If you input behind you with enough delicacy to not induce a run and hit grab, that is one way. If you buffer a control stick flick and a grab and release the grab button input within the buffer window to not cause a shield buffer, it will frame perfect turn around grab.