The technique I use is more of a "front/back"....kind of like what Weckl described in his video from the '80's, "Back to Basics." It is not "heel/toe".....I think of it as "front of the ball of your foot/back of the ball of your foot." When this technique is played fast, it LOOKS like a slide, so some might call this technique the slide....but I don't think of that way....what looks like a slide is really just the result of the "front/back" motion.
If anyone has interest in checking it out further, I wrote an article about it at:
This technique has worked for me for over 30 years. I can promise you it works like a charm once you master it.