a few weeks earlier...

Knothead stepped out of the lift into the 6th floor corridor. He had a present for his sister, Splinter in his hand, it was their birthday so he had gotten her an iPad pro tablet she had been after for her running, and a box of chocolates. He reached her door near the far end of the corridor and knocked three times in quick succession; it was his knock so that she knew it was him. he pushed the door open and was surprised to see Splinter lying sideways facing him on her double bed with only her purple skirt on, and she smiled.

"Oh! You got the iPad pro! Thanks so much bro. And chocolates... I bet these will taste nice. But maybe that won't be the only thing I'm tasting tonight..."

he had thought that they were going to wait until their 24th to have sex, but he wasn't thinking that as she got up off the bed.

"I know we were going to wait for our 24th, but I'm just as ready for this as you are. And besides, you were right, no one will know, not even aunt Winnie & uncle Woody. But we do what I want tonight, yeah?"

"Oh, yeah. Whatever you want, " Knothead said, a smile on his face.

"Well," Splinter began, her cheeks blushing, "I've always had this fetish for... well... shit. I've been into it since as long as I can remember." "We don't need to do anything if you're not the same, I just wanted to tell you..." She added hastily, her voice trailing off.

"Wow, sis... That's..." he began

"I knew you wouldn't feel the same. It's fine, forget I mentioned it."

"No, no Splinter, it's great! I'm the same, but I haven't ever told anyone until now."

"Really? That's amazing, Knothead! This alone is a great gift. Do you want to do anything tonight, or..?"

"You bet I do. What do you have in mind?"

"Well, do you want to live out your fetish fantasies?"

"Hell yeah I do!"

"Want to play it equal or from the slave angle?"

"What if we do it equal tonight and go more extreme some other time?"

"That works."

And then Splinter reached down to undo her skirt, but Knothead stopped her.

"Let me, madam." He said, feigning a posh accent as he went behind her and moved up behind her back, his erection pushing into the crack of her ass.

"As you do, gentleman." she giggled.

Then he moved his hands down the sides of her curves, began pulling her skirt down, and let it drop to the floor to her feet in one swift movement, and Splinter stepped out of them. He gave her ass and tailfeathers a gentle squeeze, and she giggled again.

"Wait a minute, close your eyes," Splinter said. "Now lie down on the bed."
She positioned her pussy just above Knothead.
"Open your eyes."

He opened his eyes and saw Splinter's wet pussy sitting just above him. Knothead knew what she wanted and didn't hesitate. He stuck his tongue into her and flicked it around inside of her. He loved the taste of her love juices, and lapped them up. Then he took his tongue out and punched his finger in and thrusted. she moaned, and he slowed down and put in a second finger.

"Oh yeah Knothead, you know what I want."

He started licking her swollen clit, and made circular motions with his two fingers. Splinter kept moaning, then she farted. Knothead stopped abruptly, and realized she was ready to do what they both fantasized about. Splinter knew what he was thinking, too.

"Sitting up or lying down?" She asked him, referring to if he wanted to sit up with her behind in front of his face or lying down with her on top of his face.

"Sitting up," he answered.

He didn't know why she was asking him for his preferences, rather than doing what she liked better. It was her birthday, after all. He didn't mind though.

She positioned herself so that she was now lying on her tits and had her ass in the air. She let another fart out. They didn't smell of anything, apart from a faint whiff of shit. Knothead relished the smell of the inside of his sister.

"I'm gonna pee Knothead, get under me and catch it!" She squealed excitedly.

Knothead guessed this was her first time doing it with his sister, and that she must be just as excited as he was for this. He complied and positioned himself under her pussy, with his mouth inches away from his urethra. Then she started to piss into his opened beak. There wasn't much hotter, thought Knothead as his opened beak filled with the more salty than bitter tasting liquid. Knothead realized that Splinter had actually gone and made it comfortable for him, by drinking a lot of water to make it less bitter and give more. When his mouth was full it dropped onto the bed, but that was ok. Knothead would take the duvet and sheets to the laundry room and wash them for her. The stream of pee from Splinter slowed down and Knothead made a game of trying to catch the drip and the flow diminished.

"Like that, Knothead?"

Knothead nodded, his mouth full of Splinter's champagne.

"Well you'll love what's next." She said, teasingly.

Knothead smiled, as the last of her pee went down his throat.

"Lick my asshole, Knothead!" She pleaded.

Knothead put his beak forward and licked her ass which was disappointingly clean. He swirled it around inside her anus and she shivered. She evidently liked it. Then another fart blasted out of her hole and straight into his face. He reveled in the nasty but heavenly smell and saw her anus opening to let a rather sizable turd through. He poked his beak in and licked the turd to try and get a taste of it, and found that he did really get a taste from just licking the face of it.

"Stick your dick in my asshole Knothead!" She demanded firmly but gently, in a way which showed she was firming up to the more dominant part of it. It was all role-play though, of course.

Knothead got off the bed, and untied down the orange bowtie he was wearing to show off a big 9 inch dick, that splinter's eyes widened at. then Knothead stuck his dick inside her wide puckered asshole and felt... shit. (There are really many ways to describe it really.) Splinter moaned while Knothead is deep penetrating her ass and a few seconds later Splinter's turd met Knothead's dick. He rubbed his cock against her turd, which got him a loud moan from Splinter and then he took his dick out. Her turd was flat with her asshole now, and Knothead stuck his tongue out to bridge the gap between her hole and his mouth so that the turd would slide down into his open mouth. The turd poked its head out of Splinter's asshole and Knothead ran his tongue up Splinter's pussy, up her crack and over the turd. He put his tongue back in the place between his mouth and her asshole and let the turd come out. It let the rest of its body through and Knothead realized it was pretty long. He gave up on the bridge idea and slid his mouth over the unbroken moist turd still moving out of Splinter's asshole. Eventually Splinter's sphincter contracted and cut off the firm yet moist turd, which was now sitting in Knothead's mouth. It was just over 24 inches long. Even after a massive Mexican meal Knothead had never passed a log as big.

"Oh... That felt good," Splinter said, "What are you gonna do with it, Knothead? Want to eat it or do something else?"

Knothead had tasted his sister's shit before, and was ecstatic to taste. But he also had another idea in his mind. He reached a compromise, and ate half of Splinter's log. It felt hot and moist, but tasted sweet and creamy. It was different to how his own tasted. Knothead's shit usually tasted a bit more bitter and dry, while Splinter's had a sweeter taste. they knew it all depended on what they ate, she had looked it up on Google and found that soft fruits like banana and avocado gave soft poop and lots of fibers gave nice, firm logs like the one in Knothead's hand. But he needed to do his plan that he knew she would like.

"Lie down on your back, Splinter." He said.

Splinter changed position and lied down, and Knothead moved in and with the firm log still in his hand, teased Splinter's clit with it.

"Oh, Knothead, that feels soooo gooood!" She exclaimed, "Stick it in my pussy, make me dirty!"

Knothead complied and moved the front end of the turd down to between her pussy lips. Splinter reached down and stretched her pussy open to accommodate her new resident. Knothead carefully pushed it in, careful not to mash it up, and Splinter squealed in pleasure as she was penetrated by the turd. she shuddered as he pushed in it more, and then he started to move it back and forth, slowly.

"I'm being fucked by a turd! I never thought my fantasies would come true!" She squealed.

Knothead smiled and this and continued, until Splinter came up with a new demand:

"Lick my turd filled pussy, Knothead! Get yourself dirty!" She demanded.

He brought the turd back so that its head was just poking out of her woodpecker pussy, and started licking her and mashing the poop between his lips, coating her pussy in shit. He flicked his tongue around inside the brown hole, and then she gave him another command:

"Now fuck my dirty pussy, bro!"

She squealed in delight and turned to put herself in the missionary position at the end of the bed, her shitty pussy dripping her sweet love juices mixed with sweeter shit. Knothead gave her pussy another lick, savored the taste, and placed the head of his cock between her pussy lips. He slowly pushed it in, and when the head was past Splinter squealed again. She flicked her head to put her red hair behind her. Knothead pushed in a little bit more, and started to thrust, his dick already getting coated in the smelly mix. He got faster, and Splinter made a continuous moan. He went a bit slower, then suddenly sped up again and was nearing his climax,

"Wait, don't cum Knothead, I have a special treat!" Splinter managed to say between her moans. "But first bury your beak in my smelly pussy so that I know you love me!"

Knothead enthusiastically obliged and pulled his dick out, and stuck his beak in between the lips which harbored the nasty mix of shit, piss and love juice. He spluttered when it entered, but persevered, and then picked up some of the bitter acidic mixture, his shit covered cock getting even harder than it was already.

"Okay Knothead, close your eyes and lie down on the bed." Splinter said.

"I wonder what this surprise is... " Knothead said, but he already had an idea of what it was.

He lied down and closed his eyes, and moments later he felt splinter's tongue running up his dick. He couldn't resist opening his eyes, and saw her licking the shit off of his cock. Her eyes moved up to meet his, and he gazed into her blue eyes. They held each other's gaze for a solid 39 seconds, then broke and went in to kiss each other. Their dirty lips met and Knothead's tongue roamed inside Splinter's mouth, which he knew well already and vice versa. They tasted the shit in each other's mouths, and kept the intimate kiss for a minute. Then they broke apart and she turned around to show her dirty brown chili woodpecker ring bulging.

"I have some more, if you want it," She said, smiling, "but this one might be a bit different & runnier than the one I pushed out."

"Oh, I love runny doo-doo." Knothead replied, grinning.

She moved closer so that her tightly closed yet bulging asshole was facing horizontally just above Knothead's cock, and then she released. She let out a few wet farts, and he caught a glimpse of whitish-brown poop inside her asshole, before it landed on his white feathers. The rest came out a bit faster, like a Mr Whippy ice cream dispenser, except this was a hundred times better than any ice cream. It also landed on his balls, layering over the shit already there but he put his hand on her ass and maneuvered it to let it fall down onto his rock hard cock. It hit the head and Knothead shuddered with pleasure. It continued to dispense out of her asshole for another 10 seconds, then it abruptly stopped and clenched. She looked around and smiled at what she'd made, she could smell it too. It was intense, and it was obvious she'd eaten something spicy and creamy from how hot & sweet it felt on his crotch.

Splinter got up on her knees and turned around so that Knothead could see her vagina which was still covered in a brown mess, and before he knew it she was pissing on his chest. He bent his head forward to try and catch some of it, and she shuffled closer in her knees, but she ended up just spraying pee everywhere but his mouth. It ended as quickly as it had started, and Splinter remembered what she was doing. She bent over, scooped up a handful of her poop from Knothead's feathers and started rubbing it on her breasts. She bent over further and started rubbing them on the still warm soft poop that had gathered at the base of Knothead's penis. She moved both her tits closer to his cock until both tits met it simultaneously. It was an amazing feeling for both him and her, and then she started rubbing them up and down his shitty cock. When she sensed Knothead was close to his climax she stopped, and looked at the disappointed look on his face.

"Our birthday, remember?" She said, with a wink.

She took off her tits and licked his cock. She slowly got a bit stronger, then she kissed the top of the head where his urethra was. She placed her lips on his shitty head, and she savored the taste before she started sucking on his head. She started to move up and down the top half of his shaft, going deeper with each suck. Eventually she reached the point where she gagged on his big meat log, and a shit-saliva mix leaked out of the sides of her mouth. The quickly sucked it back in and continued deepthroating Knothead as he moaned.

"Oh Splinter, yeah. Oh, oh, I'm gonna cum!" He moaned, and with that he blew his load in Splinter's mouth. They both moaned, and she brought her mouth off of his cock and swallowed his rather large load.

"Happy birthday, Splinter." Knothead smiled.

"Well that was the best birthday gift we've ever had. We should do that again sometime."

"Definitely."

"But we made quite a mess there," Splinter said, gesturing at the bed covers stained with sex juices and shit, "and it is our birthday, so..."

"Don't worry, I'll clean up." Knothead replied helpfully.

"I'll see you at our party later." she said as she watched him gather up the bed covers and heavy-duty mattress protector.
"We both better have a good shower; we both stink."

"Did you just realize?" Knothead chuckled, "right I'll stick this in the laundry and next thing you know it'll be back in your room. See you at our party."

"See you there..." Splinter said, as he had already gone out the door.