Hi,
I was looking at a video on the forum in which the author folds a thin strip of foam around the thorax which encompasses the wing material and the hackle. Then he wraps thread tightly around all this gathered material horizontally to sort of form a notch to keep the hackle, when wrapped, in a horizontal plane.
After wrapping the hackle, the foam material is trimmed close.
poor explanation, perhaps, but the video is available.
This is a technique I first came across on one of Steve Thornton’s flies (Virtual Nymph). He uses it on his CAM Emerger. I don’t know if it was his idea originally, I shall ask him when next we speak. It does help “neaten up” the parachute. On the CAM it is used to help tame the CDC barbs wound with the hackle.