my ex-girlfriend was the same way. her feet were very ticklish but her toes were even worse. I didn't find out about her toes for a long time, I was giving her a foot massage and I started to move my finger between her toes and she jumped and screamed. I asked her what was wrong and she was like "that tickled so bad"... music to my ears. I went inbetween each of her toes and she just screamed and tryed to pull her foot away. She was a hysterical mess by the time I was done with that part. She always jerked alittle bit from random tickles during a massage but nothing like that. From then on when she asked for a foot massage she would just grit her teeth and try to stand having my finger run between her toes. I found out later that writing on her toes with a pen drove her wild as well. She eventually told me on a scale of 1-10 her feet were like an 8 and her toes were like a 9.5. ah good times