Instead of having to go out and buy one, you probably already have one. If you have a grunt call which you can pull the reed out of the barrel of the call, all you have to do is move the o-ring (if it is equipped with it) up to fawn bleat, or estrous bleat, varies by the call. This is what I do to produce my fawn calls and it works very effectively. just give the fawn bleat an added drawn out distressed tone, and it will sound like a fawn in dire need of help. This is an inexpensive way, and a convenient way to use the call for it is right there, all in one with you grunt call, and your bleat call.
"Look what venison does to a goofy guitar player from Detroit? I'm going to be 54 this year and if I had any more energy I'd scare you."
- Ted Nugent