Hey whats up. I'm a big P-nut fan myself. I've seen them like 26 times or so and watched the video in slow-mo and learned his techiniques. I know, I'm a 311 freak!
He's doing this:
rt=right thumb slapping
lh=left hand percusive slapping
rp=right hand pop with index finger
Its a pattern of 6 moves
rt-lh-rt-rp-lh-rt
in 16note triplets I believe.
Its weird at first but with practice you will get it up to speed. Download the Primus tune "Laquerhead" Les does the same exact percussive bass fill at 1:08 during the song. Good luck, I'm actually off to see 311 tonite! This is too weird.