I can role play something that connects in me, where it resonates naturally. For that reason dad/son, incest, another submission-based role plays are those that have the most resonance. I think that role play can be a fig leaf for touching something fundamental, vulnerable, and powerful inside ourselves. @tallslenderguy alluded to this.
One observation I'd make is that role play can give us permission to let parts of us out and experience them when we might not otherwise be able to. We're dealing with deep parts of our psyches and it can require aftercare as @find91 quite rightly points out.
It's like going on a hike into beautiful natural country. One couple might use a map (role play) to get where they are going, while another might just read the terrain and see where it takes them naturally.
A man who embeds his cock in my mind as well as my cunt can get everything I have to surrender.