The pizzle nymph was featured in Total Fly Fisher about 2 years ago (sorry, do not remember exactly which issue). There was also a video of Steve Cullen tying this fly on
Total Flyfisher Magazine, which may still be available. The recipe is listed below:
Hook: Hanak 260 BL (I use a Kamasan B160), size 12-14
Thread: Black
Bead: 2.8-3.5 mm tungsten bead
Underbody: 3-4 turns of lead wire, tucked up behind bead
Tail: olive partridge
Body: dubbing, olive (use a fine, slightly spikey material - I use rabbit)
Rib: medium copper wire
Flashback: medium holographic tinsel, green (peacock and pearl also work)
Thorax: dubbing, brown
I tie this pattern in a range of colours: a brown body with an orange/pink or red thorax work well.