Goose, I use a Nekker knife, same as Phil.
It has a dull blade (inside curve) and a sharp blade (outward bend).
When you are doing the tough stuff, you use the sharp side (outward bend) and sort of shave to get fat roll'n & started, then flip to dull blade to finish.
Flip'n from dull to sharp (an make'n it look easy) comes natural after the first 100 or so Coon...LOL.
OK, everyone re-watch the video and 'see' what you are 'looking at'. He's using both blades.