Sorry for the kinda long story but 2 years ago while I was studying away, I rented a room in a small apartment owned by a couple (they liked to go out a lot so we were alone most of the time) and a straight guy rented the other room, we became friends shortly but he didn't know about my sexuality, I started finding him hot over time and whenever he was away, I sneaked into his room and took all his underwear to jackoff (sniffing all his boxer briefs,
never missed any of them during my sessions while I also jacked off on his socks, making sure I didn't cum into them)... but that's another story
Anyway, I have this thing where I can feel extremely horny and pretty much lose control of myself and my sexual desires, daring to experiment with things I would usually dislike... anything goes, basically.
And I never considered any guy's feet (or feet in general, it never did anything to me) but I had one of these moments and once I was in his room at night (he didn't mind me being there to work or anything), when he fell asleep I sucked his toes but holy shit, it felt so amazing, I made sure to feel all his taste and smell, took full advantage of the chance especially because he was a heavy sleeper so he wouldn't ever know and of course I took my sweet time doing it.

Him being straight made it much more arousing, like a forbidden feeling, what if he felt it and woke up? My mind was so full of excitement I just lost control and went for it for a good while but I stopped (fearing he'd notice) and I was so fucking aroused. 2 years later I remember that and it's still a very arousing memory.
That's pretty much when my new feet fetish started. The thing is, I rarely like feet to be honest, it heavily depends on the guy's body and face, if I like them then I'll definitely be wanting his feet, his toes, everything.