Mount a Firehole 316 size 10 at a slight downward angle and start olive thread, running it all the way across the back of the shank. Trim the tag.
Tie in small gold wire and bind it down. The underbody does not need to be tidy on this one. All of it gets covered.
Tie in a 1/8 in strip of olive scud back, taking the thread up over it at the rear to build a little hump, then bring the thread forward and leave it at the eye. Be careful not to knock the bobbin off.
Tie in a custom dubbing brush, a brush rather than a dubbing loop because it is stronger, and wrap it forward. A thick brush needs fewer wraps. Preen the fibres back with each turn: they want to go everywhere later, and this keeps them out of the eye and saves trimming.
Leave a small clear space at the eye. The scud back drops into that gap and will not slip forward on you.
Divide the fibres with your fingers, lay the scud back over the top, do not fuss over centring it, and secure with wraps back over the tie-in. Trim.
Rib the gold wire forward, working it through the fibres as you go, and flush-cut it off.
Whip finish, trapping any stragglers, and tidy the head.
Take a stainless steel brush to it, first to free the fibres you trapped under the wire, then aggressively over the whole body to build the bugginess.
Pull the fibres down and cut them a little longer than the hook point, so they spring back up when released.
Run a little Loon Flow along the top of the shellback and over the thread at the front, both sides. Let it soak a second, turn it, and cure so the back sets into a ridged, buggy shell.