My bike doesn't do this, luckily, but I've read that to make it stop, you just need to touch the top tube with one knee. Maybe someone who has this problem can comment. I'm always thinking about it as I approach higher speeds, just in case. (But it hasn't happened up to 49 mph- and I doubt I will be going much faster than that!!!)
When I apply the brakes, both for road and MTB, I use three fingers on the rear lever and two on the front, and apply equal pressure, but I don't jam on the brakes, I start very gently and increase pressure as needed and as I see how my bike responds. On the road, you can lightly feather the brakes, or, if going fast, where you don't want to ever let off completely, you can apply more pressure, then less. I, for some reason, am afraid of overheating my brakes/wheels/tires, and I don't know if this is a logical fear or not, but I try to give them a break intermittantly, not hold a steady pressure the whole way down.
Also, I try to plan ahead, and slow down _before_ a curve, so I can then just glide through it without having to brake as much.
The more you descend like this, the more comfortable it will get for you- especially if you can follow other riders through- but do your own thing at the speed _you_ are comfortable with.
Nanci
PS, I have a stock/came with the bike carbon fork.
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"...I'm like the cycling version of the guy in Flowers for Algernon." Mike Magnuson