To get the feel of how the slider should roll off of your index finger, use this grip and practice at half speed and roughly half the distance to the mound.
“Can you, in a million years, imagine another female senator - Kay Bailey Hutchinson, Claire McCaskill - reacting to being called 'ma'am' like Barbara Boxer did? This is the kind of sanctimonious self-absorption on the modern left that makes my teeth itch.”