I enjoy this old-timey-new-timey-good-timey song from Lee.
Lee's been helping out at London Harmonicas quite a lot the last few months and has been talking a fair bit about how he uses a combination of tongue blocking and lip blocking to switch up and down the harp with agility.
He anchors himself with a lip-block embouchure and switches to tongue blocking to move up the harp, then switches to lip-blocking to get back to home base quickly.