A few days had passed since you had fused with Kim's anus.  In that short amount of time, you had grow used to the smell and taste of Kim's rancid, seemingly endless gas.  You didn't have much of a choice otherwise, but Kim's regular massive dumps were so much worse that you preferred the lesser of two evils.  The giantess had spent a majority of her week relaxing at home, where she'd spend hours binging awful reality shows while gorging on huge amounts of food.  She'd still make an effort to exercise, and her high-intensity workouts drowned you in sweat and jostled you endlessly, leaving you especially nauseous and disoriented.  At night, she finally relinquished her bowels into her poor toilet bowl, masturbating just as intensely as she had during your first night with her.  It was embarrassing, but worse than that was how quick Kim was to assure you that you had nothing to worry about, as nobody knew where you were, let alone was coming for you.

The long days spent trapped in Kim's rear were mostly boring, when not disgusting.  Kim couldn't be bothered to talk directly to you all day, so most of your time was spent in isolation, where you'd wait for a fart to bubble out of your mouth and stimulate you in at least some way.  Believe it or not, you were having a harder time with the boredom than the gas.  It was a daunting experience, but you continued to play along with her game, knowing that eventually Kim would take you to the doctor.  At least, that’s what she had promised you every night after she'd dump ungodly turds through you, and her promise was the only thing that was giving you hope.

Today seemed to be the day, as you could tell from deep inside Kim's booty that she was currently driving.  Knowing it was the end of the week, you began to feel elated, despite the fact that Kim's entrapment was causing you to grow weaker and weaker.  Each day your mouth was a little harder to open, and your speech was starting to lend itself to more flatulence than it had at the start of the week.  When you communicated this to Kim, she only laughed, but would always conclude the night by saying, "You'll be home soon."

You heard Kim say a few things to people in the outside world, but were struggling to make out any of the specifics through her bassy butt.  Eventually though you heard Kim open and close a door, and knew salvation was going to be at hand soon when Kim began stripping.  Kim then bent over and spread her cheeks open, giving you a chance to see the room for yourself.  As your eyes adjusted to the brightness, you were confused.  This room wasn't a doctor's office... but it did look vaguely familiar.  "Mistress Kim, where are we?  This doesn't look like a doctor's office."

Kim began laughing cruelly out loud.  "Of course it's not a doctor's office!  It's the tanning salon."

Your heart sank as you heard those last two words.  Screaming in fear, some gas came out of your mouth before you could speak.  BBBRRR-- "b-b-but Mistress, you said you'd take me to the doctor if I behaved!"

Standing up and turning on her tanning bed, Kim was still laughing.  "Yeah, I guess I did, hahaha.  But you've just done such a great job back there this week, that I figured I'd reward you in a way that benefits both of us.  Another hour in here, and we'll both look even sexier than before.  You'll really be right at home!"  Kim put on her sunglasses and crawled in to the tanning bed, while you screamed out more flatulence furiously.  "Come on Pooper, calm down.  You know what I'll do if you don't quiet down."

"But Mistress, if you do this, it might not be possible for me to ever escape!" you cried out, having to close your eyes as Kim spread her cheeks open.

"Why would you want to escape, Pooper?  This is your home now!"  Kim continued laughing.  "Now get comfortable, we gotta make sure my butt looks perfect!  Or rather, our butt!”

Farting in defeat, you lie helplessly as you begin to feel yourself bake more and more into your host.  Hearing your host moan in pleasure, you sank deeper into her anus, knowing you were never going to get out now.  For better or worse, Kim's ass was your new home.

****

Years passed, at least, that was what you assumed.  There was no way for you to keep track of time now, as you were nothing more than Mistress Kim's asshole now.  Enough time had passed that you were no longer upset or saddened by your existence.  It simply was your life, and you accepted it.  You had made peace with being Mistress' anus, having gotten used to not only her gas but even her poop.

The rank smell and awful taste had surprisingly grown on you, though you suspect that this was something that came with your new role.  Lots of changes had happened to you gradually since Mistress kidnapped you.  After several more trips to the tanning salon, you were fully identical to Mistress' skin tone, and your body looked just like her original pucker.  Your mouth had long been gone, instead traded in for a sphincter that Mistress controlled for you.  It was far too important and powerful a muscle for you to handle, but you knew Mistress thought of you often, as she would blossom it in and out for you in between farts and shits.

A few greasy ass hairs had even sprouted on you, further trapping you within Mistress, though by now, you didn't even dream of leaving her.  You were actually honored to have been chosen by Mistress for such an important role, and thankful that you were a part of such a beautiful rear.  A part of you wished that you were still able to communicate with her, but every now and then she would acknowledge you by admiring you in the mirror or teasing you.  Of course, since you no longer could control your mouth, you had lost the ability to speak, causing Mistress to check in on you less and less frequently.

Your primary source of stimulation had been what it always had been: the end product of Mistress Kim's digestive process.  You welcomed it though, as her farts and poop were your primary company.  Dispelling her turds was a job you took great pride in, especially since Mistress still took such a great sexual pleasure in it every single night.  She'd speak and degrade you while stroking herself, but most of what she said was lost on you as you'd be too focused on savoring her dump.

"You really grew into this role well, Pooper.  It's like you were born for this; destined to be part of an ass as perfect as mine," she said to you one night in the mirror.  Her beautiful smiling face made you feel happy, and was the only image you could picture in your mind other than wedged panties or a toilet bowl.  "It's too bad you can't talk anymore, I'd love to know what you're thinking.  How much of you is 'Pooper' now, and how much of 'Jim' is left?"  It was nice of Mistress to pay attention to you, but you couldn't quite understand what she was talking about when she referred to 'Jim'.  Was that someone she used to know?

Looking closely at you, Mistress continued speaking.  "It's a good thing I can still make out your eyes, even with how much I've tanned you over.  Otherwise, I'd be worried that you weren't back there anymore, haha!"  She laughed to herself, relishing in how absurd it would be for you to be detached from her now after all this time.  "Of course, if you somehow did fall off now, I doubt you'd live very long.  You need me, Pooper, a LOT more than I need you, I bet."

You knew her final tease had truth in it, as your body thrived off the nutrients that Mistress' body was kind enough to supply you with.  Without her, you'd be nothing.  But with Mistress, you could fulfill your role as her anus better than anyone else possibly could.  You were her Pooper, and judging by the rumbling coming from Mistress' stomach, you were about to have you time to shine.