As snuff would go too far , i would propose to just create a rape story in which you kidnap your victim and you have to go to a park at night first.
And point with a gun on your victim and command her via chat dialog and engage oral.
Then you have the option to command them to get in your vehicle that is at this scene.
After that you arrive at your home and you have to point the gun at them certain times until you restrain her like on the S&M chain or force her to lay on the bed or ground.
After that you can do what you want with her. An advanced dialog could be implemented here .

Please think about this . This wont cause trouble and i would defintly buy it !