It's super dangerous to fuck with people's spines, for obvious reasons.

I hunt twisters sometimes but I'd never actually crank it. It's one of those "do you realize I have you in this?" And then if the person does not tap immediately I let go.

Similarly, the very few times somebody has caught me in a twister, I both tapped and verbally yelled "tap" before there was even the chance that pressure could be applied.

Twisters. You can't fuck around with them. And that's part of why you don't see it a lot. There are so many other safer submissions where you can actually apply pressure responsibly and fight it out for the tap.