For summoning monsters, I found it works once you find a good spot and just keep whistling and then running around for a few seconds. It doesn't seem to work on roads, but if you go into areas where monsters normally spawn then chances are it'll work alright. I use it to farm AP.

Also, Snap Jumper: Yes! That map thing frustrated the crap out of me too. I didn't even spot a compass, I just looked at the minimap and kind of figured it out based on that.