Bend mask to expose a straight line of hair. Clamp bulldog clip onto fur then cut off close to skin.
Hair is retained in clip, remove basal underfur.
Transfer to second bulldog clip to expose guard-hair tips. Again, clamp on first bulldog clip to grip all guard hairs. Remove all underfur and cut ends square. Adjust length to suit size of hackle required. Spin the dubbing whirl to trap the fibres.