What technique is Jonas Hellborg using in this video?

[BrandenSteele]

About 20 seconds in he is doing something I want to emulate, but I cannot identify what he's doing. It looks like double thumbing, strumming, and popping.
http://www.youtube.com/watch?v=W1I1I6J_U5Q

[reefferman]

Hey branden! looks to me like hes doing a combination of LH slap and 2 finger plucking poping with a flick down followup all mixed together. Vic and anthony use this technique alot. Heres a cool link to better explain. Happy pluckin n popin.

http://www.bassology.net/lessons/lesson1.html