I teach my horses one rein stops as an emergency brake.
The ORS is safest and most useful if you teach the horse how to respond to the cue (Sit deep, run one hand halfway down length of one rein, and smoothly pull that grip to your hip-bone). If the horse is flat out booking, he won't stop on a dime - a spiral-down is the better and safer bet (a hard ORS at speed has the potential to flip the horse), but the ORS at lower gaits will prepare him to respond to that as well.
I teach lateral flexion at a standstill, getting the horse softly yielding to the bit side to side off of one rein at a time. If he walks away while I'm asking, I just keep him bent and wait his feet out - he gets his head back when his feet are planted. At the walk, I'll say "Whoooo" in a low pitch, sit deep (normal seat aids for a downward transition) and flex his head, holding until his feet stop and he puts a little slack in the rein, then flex the other direction for balance's sake. Once he has that down to a science I'll do the same at a jog to working trot speed.
By the time we get to a canter, the horse generally has a clue that my seat aids are meaning stop and does so (or at least drops to trot) without a flex. If he doesn't, I'll pick up the one rein and spiral him to a working trot and stop him from there.
Most horses pick up the idea pretty easily and quickly. Once he understands I drop it and move on, maybe testing the brakes a couple of times a year to make sure that he doesn't need a tune-up.
ORS is just a tool, not a cure-all as some clinicians try to bill it.
@Feets: I'm no trainer except in the sense that I train my own horses for my personal use, and I've never had to deal with a hardcore bucker, but my tactic to fix it if I encountered it would be the same as yours - move those feet in a controlled way, on my terms. I would use the ORS to regain control, and then start riding forward and purposefully through some fairly demanding figure - small figure 8's, serpentines, etc. - to get the horse thinking and responding again. In such a situation I might not even worry about getting the feet totally stopped, just get a flex and get the horse's attention, and down to working trot, then release the rein and drive forward.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown