Pay attention ya'll....

I use a hands free grunt call that works by inhaling instead of exhaling.

I can do it at full draw, completley hads free and with only 2-3 inches of movement of my head.

Stops them dead and when I attach it behind my back it sounds as though it's coming from behind me so....they look right through me and past me looking for the source.

Tube that clips to your coat and the reed attaches 14-16 inches behind it. Attach it so the tube hits your mouth when you tirn your head and Voila

Away Outdoors Bowgrunter Plus. I have no affiliation with them...it's just a great product.

Here's a link to it and theres a video you can watch to see it in action.
!Away hunting products