My understanding is that "milking the collective" momentarily reduces pitch and there fore drag and let's the RPM recover.
Obviously the RPM has to be low in the first place and only really used it in anger in piston machines, but it works.
Also tried it in a 206 one day and could hold a hover with few percent less tq while milking the collective.
As far as moving the cyclic around goes it destroys lift as the TRT vector is all over the place and not acting in one place or close too it and more power is required