The thing about fantasy role-play is that it isn't about anything real. It's about something unreal ... being someone else ... doing something you wouldn't do in real life ... being as uninhibited as you possibly can be. That's taboo for me.
Like when one long-term play partner I've had dresses to show off her body and entice her daddy to do what's forbidden. For me, hearing my little girl say "Daddy, please lick your little girl's pussy" is music to my ears.
Whether it's to aggressively use her and train her as her daddy's slut or to be seduced by her to selfishly satisfy her own greedy appetite, the role-play is what satisfies my appetite for intense passion.