Here is a video someone put up on Youtube which is a perfect example of "creep". " Creep" is the shortening of the available casting arc by unintentionally rotating the rod tip forward during the "pause". It is a common casting fault with intermediate anglers and I think it is aggrivated by today's superfast tip-action rods.
In this instance, after the stop, the rod tip rebounds forward and the caster rotates his wrist forward so that his forward casting stroke starts at the point where the re-bounded tip stops.
He has consequently narrowed his forward casting arc too much and is exerting way too much energy for the short line he has out. With that short a line, there should be no swishing noise coming from the rod. He has also severely linited his distance range and will throw tailing loops if he goes for long distance casts with that much creep.
YouTube - ‪Fly Casting‬‏
If you count the strokes, pay particular attention to the fifth or sixth forward strokes. On that particular one, he creeps to nearly a rod vertical position before starting the forward stroke.
Here is the breakout in still by Gordon Judd, a casting instructor and aeronautical engineer who studies the mechanics of casting and loop flight in mind blowing detail. The caster lost approximately 19 degrees of casting arc due to "creeping".
The fix for this is "drift" after the stop. That is, moving the rod butt
via the casting arm back and up after the "stop" to EXTEND the available casting arc instead of shortening it. The rod tip should move back not forward during this move.