This cast came about when we were first learning to cast about 10 years ago. Not much in the way of information and we had to figure how to position the line to make a forward Spey cast after picking the line of the dangle. So what we did was throw the line above us, right to left following river, and then as the line came close we would make a little bit of a back cast to remove the slack line. Next we would drop the rod forward to get the line straight towards our target and then make our cast.
As we progressed we used the Perry Poke as a stall, set up or repositioning move before making our cast.
Dana's video's are wonderful on showing the cast.
Hope this helps.