Here's my only experience with foot fetishism...
When we think of foot fetishism, we only think of the bottom guy having fun, sometimes its the top guy who is getting off on it....
Met a married guy on M@nhunt, big dude, football player build, big arms, chest, nice stuff. Powerlifter with a body of death. He used to sneak over to my place before work, sometimes 4 or 5AM, told his wife he was going to the gym before work.
90% of what he wanted was for me to make love to his feet. I'd never done anything like this before. He kept me naked, on my knees on the floor while he directed me in the art of toe sucking and foot worship. Sometimes he'd grab me by the head hair and force his toes in my mouth. Sometimes he'd want me to quietly lie flat out on the floor and rest my head on his feet while he read stroke books. He'd occasionally let me suck on his cock. He'd finish himself off by blowing his load on my back as I mouthed his toes. Or he'd Bukake me while I knelt and he stood.
After he popped, he'd say "I got something for you" . He spread those mancheeks and had me jerk off with my nose up his butt.
I fooled around with that guy a couple of years. He gave me his home phone number and his work number. (Sometimes his wife answered the phone) We had no other relationship whatsoever, I never even knew his last name or anything at all about him. No conversation ever. Horny bastard though, never once declined to come over when I called him up for a 'date'.
I guess the dude had a kinky side which his wife wouldn't or couldn't satisfy. I kinda developed a mild interest in the foot stuff. It was a hot scene with this guy while it lasted though.