Correcting Trailer Swing

[Crazy Dazz]

We’ve all seen it, some of us have experienced it. Heavy trailer/boat/caravan starts weaving from side to side in increasing swings, pulling the car’s **** with it. In extreme cases this has resulted in horror crashes and death.
So what is the best method for overcoming this?
The pub wisdom was always that you should accelerate to pull the trailer out of its swing. Two things I couldn’t understand about that: When can you stop accelerating, and aren’t you simply making the situation worse by increasing speed and energy.
Others suggest that you should brake, causing the trailer brakes to engage. (Doesn’t help if the trailer’s brakes are RS.)
Opinions?

I got a bit overconfident today, and coming off a slight bend at 90k, the oscillations set in and got steadily worse. I gradually backed off the throttle, whilst still maintaining some positive pressure, concentrated on keeping the car’s front wheels within the lane, and as the car gradually dropped down to about 70k, the trailer settled down.
Kept it to no more than 80k, and had no further problem.
Interestingly, this happened when hauling an AU with an AU, with the car facing backwards to reduce weight on the tow hitch.
2nd trip, hauling yet another AU, turned it around, and whilst the tow car looked badly unbalanced, it actually towed far better. No problems at 95~100k.