I can't watch the vid, but I've seen DW use this technique for years. The windings on roundwound strings can be rubbed to get a "scratching" sound. That's simply "wiping" a small area of the string in a rhythm and style that a turntable DJ would do. Sometimes he uses distortion to bring it out a little more.
This can be done on any bass, fretted or fretless, that has roundwounds on it. The technique is not dependent on letter name notes or how they are produced on the fingerboard.
This is just one of Wimbish's many tricks - he has a lot of 'em. Given Doug's impressive discography, it's safe to assume he knows more than just tricks and weird sounds.
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