On familiar descents like Mt. Gaylor, I'll tuck in, move back in the saddle, put the pedals at 3 and 9 o'clock, put the knees against the top tube, get in the drops and go for it, after I've maxed out pedaling.
Significant cross winds and/or wet roads and/or an unfamiliar descent and it is caution.
Going down a descent on the Big Dam Bridge 100 this year, I wanted to let loose, but this was my first time down this one. A young fellow ahead of me carved his way right through a turn about half way down, no problem (where is the green-with-envy icon?). In a brief conversation with a LEO on toward Little Rock, I found out that someone rode through this turn and off the side of the hill. I'm glad a kept a more sedate pace on this unfamiliar descent.
I'm working on the cornering at speed by moving a little forward in the saddle and pointing my knee into the turn. Seems to help.
Everyone seems to say that to climb better, we need to do more climbs. Same may well be true of descending.