Hans,
I was recently reviewing your video on the Reversed Hackle Dry Fly. One of the advantages I noticed is that the tier doesn't have to switch hands when creating the collar - this in turn means the hackle pliers (I use the same type you use) are less likely to slip off the feather.
So, I'm tying some up yesterday, it's all good, except that my feather is twisting as I create the collar (like it always does). I notice in you vid that your hackle doesn't twist. It seems that you are somehow rotating the pliers while winding the collar.
What are you doing?
-Steven