I once dated a very sheltered and conservative girl. We had a very typical transition from acquaintances, to good friends, to best friends. Then one day, after frequent 1 on 1 "not date" hangouts, we just zinged. We had an very awkward and emotionally charged "I really like you!" conversation, and we both found out that we had mutual feelings for each other.
So, how "conservative" was she? Well:
1. Culturally, her family believed in segregation and arranged marriages. She wanted no part in that lifestyle, but unfortunately (for her) her parents were very set in their ways. It took us a year of dating to realize that her parents would never accept me. But we parted ways as good friends.
2. On a personal level, she didn't even know how to pleasure herself (and felt the idea was taboo, at first).
So needless to say, the concept of a fetish had to be taught to her. I had to break to her in the most basic way I knew how:
1. I first asked her how seeing me made her feel, and we discussed the variety of reactions: tummy butterflies, heart flutters, etc. Basically we established that we both understood how we physically and emotionally were attracted to one another.
2. Then we talked about the birds and the bees lol. We established how important physical intimacy is, and what it entails, in a tasteful and subtle manner.
3. I then expressed how I find other things attractive, that some people wouldn't consider "typical". This piqued her curiosity, and that's when I asked her if she had ever noticed how I complimented her feet a lot, or how I enjoyed tickling. I then went on to explain how on one level, the tickling is innocent and playful, but on another I get as much of a rush from it as one would from other intimate activities.
4. She's a smart gal, so she put two and two together.
And that's how I explained what a fetish was, and what my two fetishes were, to a person who was completely sheltered from the entire thing.
I also taught her how to pleasure herself, and opened her world to something that I believe helped her explore her own body, relieve stress, and just make her over all a happier person.