Same here... horribly ticklish down there if it's covered, but if not, any touches are sensual touches rather than tickling. It's weird how that works.
YES. If it's really really light, I get an awful insane urge to rub my feet and make the itching stop! Like SilverTickle said, I can't imagine experiencing that while tied up.
Recently I was on the phone with my housemate who was asking for advice about something, and my new girlfriend, sensing the serious tone of the conversation and wanting to be evil/wanting to get me off the phone, started playing with my feet. I was wearing nylons, too, which made it even worse...
I have EXTREMELY sensitive ears - when I'm tickled there, it drives me crazy, but it's also a plus because my partner knows where to go when we're making out... does anyone else with ticklish ears find they get that transition too? Incidentally, she too has very very sensitive ears which are fun...