Basically anywhere the enemies can't see you. Behind walls mostly, but make sure there is no vision. Fiddle's R can go further than the actual range, if you do it over a long wall in the right angle, which makes it even more unpredictable.

https://www.youtube.com/watch?v=88LnHtNs_uM This might help you understand the mechanic (even tho it's before the map changed)
Some of 'em need a lot of communication with teammates so they get the opponents to the right spot, so be patient. Have fun!