I actually just had my first "exclusively feet" encounter a few weeks ago during a trip to DC. Had a client who spent the entire hour (and then some) playing with, licking, sucking, massaging, and grazing my feet with his teeth. No sex, not even any kissing. It was unexpected (he hadn't even mentioned a foot fetish prior to meeting), but definitely a good experience. I loved seeing how happy he was completely losing himself in the experience-- definitely one of the most satisfying encounters I've had.
Oof, this one is always conflicting. I love seeing my top enjoying himself while I'm in that position, but my feet are pretty ticklish and I'm always afraid I'm going to kick him in the face