To add to the Fan Throw tip, I don't actually Mash B. I piano a C to help my consistency. It can be done with any button, not just B. So the input would be: Jump, 44, C>4/5/6B. You can replace C in there with any button though.
Edit: To be more precise. There is a 5F dead frame window during a backdash (credit to gli for that info). I have no idea whether or not hitting an extra button shortens this window or not, and I have no means to prove that it does. I do know however that it helps my timing tremendously, and I can do this in a real match 99% of the time without much trouble with this method. So, it may be a glitch, it may be just a timing tool--but I think it will help Yukiko players struggling with timing this the normal way.
