(Before you read this I feel you should know that chyoa member chris_brown helped me to come up with this and that there will be scat (poop) and watersports (piss) if you don't like that don't read. If you do or don't mind then go ahead)
You are transported to a rocky area with a pool of, what looks like, mud and filled with yellow steam. "What is this place?" you ask wondering why you aren't an incubus yet. You the notice the smell "Welcome to the Sauna of Eternity." said Alenzer, stepping into the pool of what you now know isn't mud "You might've already guessed it but this isn't mud. Its crap, this place is in the Pit of Depravity a place in hell that personifies lust, and all its fetishes."
Alenzer is waist deep in the pool of crap when you feel a pressure in you ass. You begin to poop uncontrolably, so much shit comes out so fast, you moan in both pain and pleasure "Ah its began. You see in the human world the conversion fro human to demon is almost instantly, however here your changes take a bit more time..." some kind of stone starts to come out of your ass as your skin starts to slowly turn red and your tail bones form.
"The process is a different depending on where in the Pit of Depravity you are in. However the common things that occur in all of them are, your human body dying and becoming an Incubus. A tombstone to mark your death as a human appearing in some way, here you'll be crapping it out." Alenzer was neck deep in crap, while you finish crapping out say "I NEED TO DIE BABY!!!!!!!!!!!!!!!!!!!!" You continue crapping as your tail bones begin to write your name on the blank tombstone.
"It seems we've gotten to the part where you wright your name on the tombstone." Alenzer starts to get out of the shit sauna. Your skin is now entirely red, your tails skin begins to form, your cock has become massive. Alenzer is now in front of you, body covered in shit, presenting his ass. You get up, horns beginning to form, and start to fuck Alenzer's ass. Your lungs fill with piss steam and the smell of crap, your, now finished, tail intertwines with Alenzer's. The both of you moan in pleasure, as the two of you make your way to the shit sauna.
You fall in and continue fucking Alenzer, covering your body in heated crap, you fill climax coming, and speed up "Yes, yes, it is time to dispose of what remains of your human soul and become an Incubus. Once you cum, the process is complete." at that moment, you cum, it is more then you imagined possible, and Alenzer's anal hole heats up. You know the reason why and smile.
"My human soul now rests in hell." is what you say. "Yes my new Incubus, but that is unimportant now that the process is complete." said Alenzer "What do you wish to do, fuck some more, explore the other parts of the Pit of Depravity, or perhaps go to one of the many places in the Multiverse to corrupt more beings? I'll let you decide, think of it a present to commemorate the day you became an Incubus."