Fire On the Mountain Marshal Tucker Lick?

[Mel Mandville]

Hi. I'm covering this tune in my band. I've got most of it dialed except the lick over the D chord in the second chorus. The first time he plays a dropped E knee lever.
The next time he kind of slides down? Not quite sure what that is. It's kind of a swingy thing, but really cool. One of these days I'll learn how to play this contraption...
Any help would be great. I play a standard 3x5 Nashville tuning

Thanks