It is a fairly simple fly, it only uses marabou, deer hair, a few strands of flash, and mallard flank. The marabou is wrapped, starting at the tip, rather than being stacked like is typically done. The mallard flanks sit flat on top of both the rear hook and the front. But the really unique trait of this fly is the head. It is trimmed deer hair, shaped basically like a mentos candy. This shape and the slim, flowing body gives the pattern an action that is just plain epic! Use a gamakatsu stinger size 4 to 1/0 for the front hook, and a 3x long streamer hook size 6-2 for the trailing hook.
The advantage to this fly is that it doesn't have any weight to it. It is perfect for shallow water and very aggressive fish. I have used it successfully for smallmouth, chain pickerel, and rainbow trout when they are in a grumpy mood.
For trout, the best method using the Heifer Groomer is a fast jerk-strip retrieve. Give brief pauses, but generally a fish will turn away if you pause for too long while it is chasing. Fast and erratic is the way to go. When the fish takes, it will probably be explosive. Give a strong strip set and hold on.