My girlfriend recently admitted she has R fantasy.

Not that she wanna go through it but she likes the legal porn of that genre

Whenever we watched porn she always switches to that japanes train videos where one girl is used freely on subway.
I cornered her recently and asked what she likes about it and she said her ‘Reluctance’.
I said that you do realise that is kinda R and she said yes. I couldn’t believe my “vanilla” is having this conversation with me.
I got hard and went down on her while talking. I asked her if she wants to be in that girl’s place and she said no she just likes looking at it. However she came in mouth sooner than ever while watching those videos.

What should I make of this situation and how can I use it give her better sex experience regarding her kink within the bounds of legality and security?