Foot Fetish

I'm sure this has been discussed here before, but what is included in a foot fetish session and why do some ladies require a bigger donation for said service. I know is seems like a dumb ass question, but I'm just courous. Thanks in advance

Since no one else has answered, I will at least attempt to answer part of it.

Foot Fetish can include: Foot Worship, Toe Sucking, Sniffing, FJ, licking, and just having a lady rub her feet all over you.

If its just a foot session and not FS, I have no clue why a bigger donation would be required.

Why the extra? Supply and demand. Fewer girls will do it so the ones that do can charge what they want.

Thanks for you input. I was hoping to hear from a providers POV, but I understand a little better now. In a way it should be or could be part of the GFE session depending how for the fetish goes, but I do understand that every provider is different as well as every monger, I mean customer