You fuck her

As soon as you push your massive cock into her wet slit, the demon inside of you takes over, you fuck her hard and fast, after about ten minutes, you pull out of her and lay on your back with your massive cock sticking straight up in the air.

She gets the message and starts to slide down your cock until all of it is buried deep inside of her, after about fifteen minutes, you can take no more and unleash your demon seed deep inside of her, as you do that her climax hits her, her body changes into a beautiful succubus, long black hair, big tits, dark red skin.