Not sure I understand the request, but it is interesting. Why "symbolize" tickling in an image when you can just as easily portray it directly? Is this for letterhead stationery? Symbols are just that,...... symbols, and as such they always fall short of actual experience. Symbols too often are the currency of politicians and advertisers.
And while feathers are not exactly the best implement for the job, they still connote the act, and that might be the most you can expect of a symbol. I'm not happy with it, either, rest assured. But whatcha gonna do? I think the image of a feather superimposed over a sexy bare sole would be a powerful graphic,.... but again, for what purpose? Are we trying to be subtle or to sell something?
If it's just for fun, here's an old idea I came up with years ago,..... Susan and I liked to take our play to more complex places. I made a deck of playing cards, but instead of the usual suits of hearts, spades, diamonds and clubs,.. my suits were high heels, bare feet, ropes and feathers. We played poker with them, the outcome of each hand leading to some little event suggested by the suits in the winning hand (alright, this was, at best, a highly nuanced calculation) But the "symbols" on the cards did their job,.... they were just pictures,...... and you know what a single picture is supposed to be worth.