This one is on Clarence “Gatemouth” Brown.
He will sometimes slide further then the #3 of the Bb7 (10th fret, 1st string); up to the 12th fret or higher.
This is done with great speed because you’ve got to be back for the next note.
This forward whip was also played by Albert Collins who would end the “whip” with a minor third and then bend it like crazy.
Try it, it’s a great effect.