Sorry for the mass confusion.
I have a bad habit at both not explaining myself thoroughly and not reading thoroughly lol.
Anywho, to retouch on something about being grounded while trying to perform up+bs, here is a little chart to show you why the jump (whether it be tap jump like you've discovered to use or another mapped jump, like how I use Z) is so important
EDIT: When I went to pull up the thread to maybe help explain why up+bing on the ground seems so difficult, I found out that my knowledge wasn't that great of it either.
Something you may or may not realize is, when you are in a different state of movement or none at all (whether it be walking, running, in the air, etc) the region that your control stick can be in to input a special changes.
This is what the control stick region looks like for your specials while running. I thought the up-b zone was going to be considerably smaller. Then I noticed that underneath the image in Luckylime's thread, he states the following:
"While running, R.O.B. cannot perform RF specials. (with the exception of RF UP-B by jump canceling into it) "
Even though we're not certain how this physic works, it at least confirms that a jump needs to be involved to do a reverse-facing (RF) up+b.
The link to that thread can be found here:
Now onto the aerial stuff.
It works quite similar to the grounded up+b stuff that I explained in the Q&A thread.
Let's resort back to this image of the left and right (or east and west) regions of your control stick:
Now let's reference to 7:47 in my match vs Sneakytako
As you can see, I am moving left but facing right.
What I first do is input the up+b on the left side of my control stick. As long as the stick if just even a little to the left of the top notch of the control stick region, this will work. This will make ROB face left for a brief moment until some more magic happens (you might not even notice that I faced the opposite way in the video because it happens so fast). As soon as the up+b has started, I will immediately roll my stick over to the right, upward side which will cause ROB to quickly face the direction he was initially facing and bounce/boost that direction as well. The main reason why this happens is because ROB's momentum was originally going to the left, not the right. If you wanted to get fancy, you could have even started on the right side with the up-b and roll to the left which would cause ROB to bounce/boost the same direction but now face the opposite direction.
I'm going to stop here for now before I get any more confusing. I hope this clears some things up for you and if you have any more questions, do not hesitate to ask. Btw, you should probably ask this kind of stuff in the Q&A thread so other ROB mains can see it. ^_^