Whistle Training

Question:
 Hi everyone,
As many of you know I have been having issues with Lexie being aggressive/protective. After many,many phone calls and consultations with various trainiers (some of which scared me with the "choke" collar method!) I found one that uses a "whistle" training method. This sounds (no pun intended!ha) like a great alternative to the other barbaric methods. Have any of you had experience wsith this? I would appreciate your thoughts!

Answer:
 Can you tell us a little more about it?

Answer:
 Sounds like it might be similar to clicker training -- instead of the clicker you whistle.