It's hard to explain a fetish to someone. You either get or you don't; that's just the nature of fetishes. But if I were to try, there are a few aspects of this particular one. Aesthetics. Like anything else, a woman's feet are attractive when they look good. Healthy, well manicured, clean/painted nails. Just overall cute feet. And then there is the dominant/submissive relationship stuff. Some guys prefer to submit to dominant women by sucking their toes, smelling their feet, and even getting trampled. And some just like the feeling of getting their bag tickled by her toes or running their cock between her arches. My point was that she has nice feet. I can't get into the hardcore foot videos (i.e. 100% feet) but some foot worship is nice. I just like some feet mixed in with my porn.

the sensory projections in the cortex for the genitals are in very close approximation for those of the feet. If you stimulate the feet you can at times cause stimulation to the genitals through overflow via an associated connection between the neurons in the brain by the mechanism of long term potentiation. Think about it when a lot of people orgasm they point their toes or have feelings of tingling in their feet. That's why.