I once tickled a girl like this, but I dont think she had bunions. Every time I tickled her feet, her toes would move only one way, they would point straight down and curl up very hard downward, but never flex and point, or wiggle back and forth. From hearing your experience, Iam beginning to think that maybe the girl I tickled had something wrong with her feet to, although I'm not sure. Some girls whose feet I've tickled, I notice that their toes move only one way. I've tickled girls whose toes do nothing but a hard flexing motion away from my fingers, and others like the girl I mentioned whose toes would only point down. I dont know if the situation you mentioned, or the ones I did, had to do with these girls having feet problems or what. This is an interesting question.
Mitch