Anyone familiar with this technique?

[etacada]

Hi, on several ocasions while spey fishing for steelhead, I have noticed other fly guys swinging fly but as they do they flip or shack there rods as they fish. I'm assuming that the movement atracts fish but can anyone give me some details on this? Are there certain flys to use? how hard do you pump the rod? I'll take any info. loks interesting and i'd like to add it to my arsenal.

take care:) ,
chris

[Rosco]

You sure they were swinging?? They could be just throwing some mends in the line to slow the drift. Dunno though.