I was not sure if you still want your question answered. Please let me know.
Ok. I am not an expert in feet so I can opt out for another expert to answer if you wish.
Most therapists study fetishes as part of their training. Rarely would someone be an expert except maybe in fetishes in general. I'm not sure if there is such an expert on Just Answer, but I will opt out so you have the opportunity to find one. Take care!