Perry Poke
The Perry Poke can be used as a “get out of jail free cast”, (amongst other uses) usually when you have found it necessary to abort a Spey cast prematurely because your anchor point did not achieve the required position, therefore introducing a Perry Poke will still allow you to make a very efficient cast.
Apart from being used to recover a badly set up Spey cast, the Perry Poke can also be adapted to several other situations, from assisting with the delivery of a heavy or bulky fly, to being a very useful cast when using Skagit lines, as it will easily dig out fast sinking tips and allow you to deliver them efficiently to your target.
As long as your D loop is formed directly behind the fly and preferably in the direction you are going to deliver to (as with all Spey casts) then the cast will be efficient (if delivered correctly).
So basically, wherever you have placed your fly on the water, in the early stages of the set up of your cast, you can then use this technique to dump line (poke the rod tip) down onto the water in front of you (in the direction of your fly) thus affording you time to then transfer this dumped line (from the water in front of you) into your D loop behind (under tension). This newly formed D loop can then be delivered out across the water to great effect.
If this dumped line is correctly and smoothly transferred to your D loop, and formed directly behind your anchor placement, (in line with your target) you can rest assured that you will have created the casting weight required to enable you to deliver an efficient cast.