I am a big fan of Dave Hughes. I have some of his fur flies which came as part of a special edition of one of his books.
Just happened to watch his video on tying the "Anchor Wet Fly" the other day and watched him form a dubbing loop by simply loosely applying dubbing to the thread, then forming a loop by tying the thread down back to the rear of the fly; then spinning the loop and wrapping it forward.
It's just that most tiers (even with the split thread technique), form the loop first and then insert the dubbing material.
Easier to see in this video. Starts at approx 3:30.
Don't know why I haven't used this method long ago.....
https://www.youtube.com/watch?v=-3wOJymm5Pk