I'm shamelessly stealing that person idea, because I think it's an interesting question.
Personally I'm into porn involving some forms of abuse, often it's rape but it could also be just spanking or gaslight. Of course I'm not into that in real life. I know CNC is a thing, same with consensual SM and I could be into trying those one day, but I don't see myself doing that with my husband anytime soon, and it's different when it's planned in advance, which is not always the case in the story presented in porn.
I like the idea of nutting on someone's face but I feel like doing it in some kind of hole feels better and less of a mess.
As for grandmas it's not something I regularly watch and I feel like actually being there, feeling the sag, and not wanting to do something like shatter their pelvis would put me off