Middle Branch, basically any streamer can be augmented with a lip to provide action and some diving ability. The advantage of the sequin on pin is the ability to tune the action by bending the pin. Every fly pattern is different and no single lip size and angle will do the same for all.

Here's some on a foam block with a dab of epoxy applied:


Bend the pin head 90 degrees with needlenose pliers, put the sequin on and then slide it flush into the block. You can cover the whole sequin with epoxy and use thick pins if you want extra durability.

Here it is mounted on a hook:

How do I know it'll ride hook point up? Well, a lot has to do with hydrodynamics and the center of gravity. For example, a hair wing will want to be 'topside'. Just play around until it swims true and catches fish!