I have seen Michael Waddel on Realtree Roadtrips use it more than anyone else and for good reason I suppose, it seems to work. The only times I would really use it is maybe every once in awhile before a rattling sequence or when you see a GOOD buck out of range. Like these guys said, if he's too small or it's a doe, they're liable to run off. I can now do it exactly as Waddel does in Season 3 on his Illinois hunt. Put your front teeth together, cup one of your hands around your mouth like you're going to yell at someone very far away and forcefully exhale air. I give 2 "shorts" or bursts and then immediately follow with a long, drawn-out one almost as long as I can hold it without drowning out.