I have a pretty specific necro fetish where a girl dies suddenly in a horrific way and her body was brought to a mortuary to get inspected and cleaned up. There's the clear terror the girl had when her life ended and when unknown hands touched and examined her cold body for clues and signs. After that, Her body gets fixed up, made up, and dressed up before she was put in a coffin to be buried. That look of horror was gtadually replaced by serenity as she was prepared for the eternity ahead. And after the extremely loud funeral procession, she can finally enjoy an eternity of peace in a comfortable coffin, unbothered by the ails of life. However, the girl's rest didn't even last long before some sick bastard dug her up from her resting place and defiled her by filthy sexual acts. After he was done, the man then took her body to be his sexual doll, all the while the horror can be felt even on her unmoving corpse.

I think what gets me the most is the contrast of horror, peace and serenity, and terror again. The girl got her peace after a moment of agony only for it to be taken away by force. It's kinda hard to describe to people not having this specific fetish, but i did my best.