In the terms of "Auto tickling" i have once had a girl tied up laying down, spread eagle.
then i attached a bunch of strings to the ceiling and feathers on the other end. I would cut the strings short enough that the feather would just graze her skin.
Once I had my preferred amount feathers in the preferred places, all I had to do was brush against the strings to start the feathers moving (and tickling). She would start squirming and do the rest.
I think i had her there for about an hour, she loved it 🙂