...the friend thing is strange...
So, she is.. not ready to be filmed. That I get. Have you tried easing her into tickling in any way yet, or is this still in the talking phase?
I was mostly just curious if an interview might ease her into it, or break the ice so to speak so that she was more comfortable with it. But hey, if she isn't interested she isn't interested. Further I think she will remain unwilling to show skin or anything.
Actually, you know what I was just reminded of? Gabriel (I believe her name was) of tickling paradise. Her clips always had the camera focused upon her feet, I believe for similar reasons. Maybe your model would be ok with that?
I mean, I would hope she's comfortable enough with other people seeing her feet, as most girls wear sandals/flip flops/other revealing shoes, but who knows. I don't: I'm just a third, unrelated party in this situation commenting on your interpretation of the situation, lol.