The descent is a thing more difficult to describe than the climb. It is for this reason, I am convinced (and not because climbs are more arduous), that less attention is lavished upon it in cycling lore and ride reports.
The slow speed of a climb gives us time to ruminate, to form thoughts that give concrete shape to the things we are feeling. The apex ahead provides a point to fixate upon as it steadily comes into view. As an experience, the climb is tunnel-like. Sensations sharpen, with each pedal stroke growing into more defined versions of themselves. Up is up. Pain is pain. Strain is strain.
But what the climb focuses, the descent scatters. There is nothing to fixate upon, and so it cannot be grasped. The horizon tilts. Distinction between up and down blurs. The sense of time warps. A sensation arises that can only be described as a fullness, a visceral satiation that is nonetheless paired with a restless sense of urgency, of needing to merge with the distant vistas ahead.
They call them "screaming descents" because internally we scream. But whether it is from fear, or joy, or a sense of catharsis, or some other, as yet unknown, emotion, at once too powerful and too fleeting to survive outside this immediate experience, we cannot say.
The descent is not so much an experience of flying, as it is of spilling. A thorough, absolute unraveling that, even once we've come down and calmed down, stays within us, like a giddy hidden madness.