crazydiamond

But they aren't just beating the string, they're also raising the pitch gradually with the other hand.

Whomp on it with one hand while the other hand "glissandos" up and down the frettin' place. Glissando isn't a good word though, sounds too elegant.

If you were a double bassist and I write a piece in which the double-basses' E string is detuned to the point that they nearly fall off, what reaction could I expect to get from the section?

I like the rattling noise you can make with a wood block...

There isn't any specification on what kind of guitar is acceptable! Can I finally put my "Concerto for Pedal Steel Guitar" to use?

Work on long tones. Maybe play a concert B-flat (C-D-E-F-G-A-B-C) or concert C (D-E-F#-G-A-B-C#-D) and hold each note for 2+ bars at 60 bpm before moving to the next one. This helped me build my chops for more consistent notes and a fuller tone.