You begin to caress your lengthened cock, feeling like you need to just cum so badly. Standing there in the bathroom stroking, you catch a glimpse of your altered self in the mirror. This isn't you! You've been changed and altered by some malevolent force and you need to do something.
You force yourself to stop stroking and walk to the computer. If demons are real, other people must have encountered them and maybe there is useful information on the internet about it.
"Aww is my puppy horny?"
The shock at no longer being alone makes you jump at what feels like 10 feet. The succubus from before is standing right in your apartment smiling at you. You quickly grab a pillow to cover up your visible erection.
"Don't be silly." The succubus walks up to you. "Dogs don't have modesty." She grabs the pillow and throws it into a corner leaving you exposed.
"What have you done to me?" You ask angrily.
"Nothing! You did it." She laughs. "You drank from the chalice. You choose this path and I think its time for you to show some appreciation to me for not leaving you a filthy stray."
"Appreciation?" You say. "Look at me!"
"I think you look very handsome, but there is still plenty of work yet to do." She sat down on the couch and spread her legs apart, exposing her dripping pussy.
You wanted argue or look away, but you couldn't. You couldn't help but stare at the succubus' crotch. You wanted her pussy. You needed it. Still naked you fall to the floor in front of her and stick you tongue into the succubus. You begin to lap up her juices greedily, excited to find they taste a lot like the nectar you drank out of the chalice earlier. The succubus begins to moan as you slide your tongue around her vagina and clit. The more you lick, the further your tongue seems to go inside. The succubus screams as she orgasms and you eagerly lick up her arousal. This goes on for who knows how long, until she leans towards you and says,
"Say my name." Licking her impossibly deep inside you speak the only word you could possibly think of at that moment.
"Mistress." The moment you say "mistress" you orgasm hard despite not having any physical contact on your genitals. The cum splatters onto the couch and your new muscular body. You fall back panting and exhausted.
"What a good boy." The succubus said. "I love your new tongue."
You sit up and feel your tongue hanging out of your mouth. You reach up and touch it. It was long, thin and rough. It was the tongue of a a dog.