Go for a dive! That's what most people forget when they try BS Disasters. Your body needs to be in the transition while doing it. Not on the deck. That will prevent you from overrotating.
It is a bit scary at first, but just try to dive your head a slight bit forward when you do the rotation.
Also, don't fully rotate. Maybe keep it at a good 170. Overrotated back disasters are the worst and can actually be pretty dangerous too.Lots of hangup-potential.