Fisting had been one of their main go-to kinks since very early on. Although Derek could trace his interest in it back to the years he spent in New York’s gay scene after the fire and Peter’s interest in it even further back, the first time he thought of it in regards to the three of them was thanks to some unintentionally suggestive things Stiles had said while they were dealing with the Alpha Pack.
“Okay, okay, big guy. Let's see it. Let's see that fist. Big, old fist. Make it, come on. Get it out there. Don't be scared. Big, bad wolf. Yeah, look at that,” he had said, seemingly unaware of the innuendos or of how flirtatious he sounded. And Derek had played along, just as he always did with Stiles.
He’d done his best to avoid thinking of Stiles in sexual situations while he was still underage lest his own past come back to haunt him, but of course Peter caught on to both the innuendos and how Stiles affected him. Derek had wanted to wipe the smirk off his uncle’s face and trying to stick the fist he’d made for Stiles as far up Peter’s ass as he could seemed like just the thing to do it. But that had been a fleeting thought quickly pushed out of his mind by the direness of the situation they were in.
It wasn’t until a few years later, after the three of them entered an official relationship, that he’d been able to make those stray thoughts a reality. He’d started with a fist in Stiles and Peter each, then they had formed a chain with Stiles fisting him while he continued to fist Peter. But this evening Stiles needed to study for finals, so it was just him and Peter in the playroom on the top floor of their house.
After sending Rex and Harley to “help” Stiles with his studying, they started out in the 69 position on a large padded floor mat. While sucking each other’s cocks, they also fingered each other’s asses open with the aid of a bucket of lube each. They worked in unison, easily starting with four fingers added one after another and using open-ended plastic syringes to add liberal amounts of lube into the other’s hole. They made noises of interest around each other’s cocks as they worked their fists in, mirroring each other’s movements.
It was a fun twist on the usual 69 position, but the angle made it difficult to achieve much depth while still being able to suck each other’s cocks. Wanting more, Derek pulled his fist out of Peter’s ass and moved into a crouch while keeping Peter’s fist inside himself.
“Hey, I was enjoying that,” Peter griped.
“You’re just miffed I beat you to it,” Derek replied as he sank half way down Peter’s forearm, using it like a dildo. “I’ll make it up to you with some of your favorites after.”
“True, and I guess that’s fair,” Peter said as he watched Derek’s progress. He slipped his free hand inside his ass to fill the void Derek's fist had left and idly played with his hole.
Derek paused to add more lube then smoothly sank down on it until his ass met Peter’s elbow on the floor. He rose all the way off it and went back down, feeling his ass ripple around Peter’s fist as he started to ride Peter’s arm faster with each new pass.
“Want more?” Peter asked as he felt Derek’s ass really start to loosen up.
“Ngh, yes,” Derek groaned as he heavily sat as far down as he could and twisted around. The bulky arm created a really nice pressure against his rear anal wall as he bent forward and slid off it a bit in order to get on all fours. It filled him again and flexed as Peter moved into position on his knees behind him.
Peter pulled his arm back then plowed forward until his elbow was lodged in Derek’s ass to give him exactly what he wanted. The resulting gasp of pleasure from his nephew was music to his ears as he aimed his thrusts slightly downwards to grind into Derek’s prostate before leveling out to go deep.
He wouldn’t be surprised if his fist created a visible bulge in Derek’s abs at the new angle, but he was focused on the Hale Triskele tattooed on his nephew’s back. Derek had gotten it as a form of penance and remembrance after the fire but Peter never blamed him for what happened and was proud of who Derek had become. He was more than worthy of wearing their pack symbol and it suited him well.
Derek felt a tingling under his skin as Peter traced his tattoo with a feather light touch. Goose bumps spread as the wet fingertips glided down from his wide shoulders to the dip in the small of his back and formed a heavenly contrast to the heaviness of Peter’s arm moving deep inside him.
The hand caressing him snaked its way around to jerk him off, still slick with lube from Peter playing with his own hole earlier. At the same time, the fist inside him stopped thrusting and pressed firmly against his prostate, Peter rolling his knuckles into it. The final straw was when Peter leaned forward to nip at his earlobe and told him to “cum” in a growly voice that brought him over the edge. Peter couldn’t order him around as a wolf, but that didn’t mean a well-placed growl wouldn’t hit the right buttons of his libido.
“That. Was just what I needed,” Derek panted.
“You’re welcome, dear nephew,” Peter said as he sauntered over to one of the two padded sex-tables in the room and lay down on it. “My turn,” he said as he held up his legs to expose his ass. Derek rolled his eyes fondly with a small smile as he got up and followed; he did enjoy the challenge of slowly taking his uncle apart and making him cum.
Derek lubed up his arm and easily slid it into Peter’s ass up to the elbow without meeting any resistance. He thrust in and out a few times then paused to vibrate his arm up and down, making Peter moan as he melted into the feeling. As Peter opened up even more, Derek pushed forward to sink his elbow and the start of his bicep in. To go deeper still, he backed off slightly and pushed in with a steady pressure, watching as his bicep was slowly swallowed up by Peter’s ass until it was all the way in shoulder deep.
Peter’s eyes fluttered closed with his mouth open in a silent gasp at the intensity of being filled so completely. “Fuck yeah, that’s a good stretch,” he said in a tight voice as the massive bicep and then elbow were pulled out of his ass and thrust all the way back in over and over again.
“Good, you’re doing so good,” Derek said as he kissed Peter’s inner thigh. And his uncle was good in his own way. Even if his words and actions were sometimes a darker shade of morally gray, his position as the Left Hand of the pack was essential to their survival.
Peter let out a slow breath as Derek finally pulled out all the way to lube up his other arm. The hair on both his arms now matted down in slick swirling patterns.
This time Derek kept one hand around his arm outside Peter’s ass to feel as he leisurely slid in just past the elbow and pulled it back again, then alternated arms before the first had completely left Peter’s ass. The smooth rhythmic motions were equal parts soothing and arousing, allowing the two of them to relax into it.
After coming down from the high of going shoulder deep, they were ready to heat things up again. The steady “slk, slk” of Derek’s arms working in and out became “plop-slk, plop-slk” as he moved faster, pulling out all the way before punch-fucking back into Peter’s ass. Peter’s hole gaped in the brief moments before Derek’s alternate arm plowed in to fill the void.
Peter’s arousal increased exponentially and he started letting out low moans of pleasure at the unrelenting fast-paced stimulation. The moans built into a small roar as his anal walls pushed Derek’s arm out and kept pushing while he threw his head back in ecstasy.
“Yeah, that’s right. Show me that fuckin’ rosebud,” Derek said huskily as he played with the healthy red inner walls that bulged slightly outwards from Peter’s wide open rim.
Peter brought his head back up with a filthy grin and glowing blue eyes and watched as Derek bent down to lick and mouth at the exposed flesh. He kept his hole extended until Derek pushed it back in with his fist, smoothly driving in just past his elbow.
This time Derek only pulled back to the wrist before driving in again in short strokes, making sure to hit Peter’s prostate as often as he could to try to bring him to his climax.
Peter loved the attention he was receiving and was smug that he still held on to that last bit of control when Derek was working so hard to make him cum. But then Derek lowered his mouth onto Peter’s dick to deep throat it while continuing to fist him and Peter was gone, knotting Derek’s mouth.
With a knot in his mouth, his nose in Peter’s neatly trimmed pubes, his bearded chin resting on Peter’s soft ball sack, and his arm part way up Peter’s warm, slick, pulsing ass Derek knew he wasn’t too far from his own orgasm. He backed off of Peter’s knot to catch some cum on his tongue then pulled off completely to receive another generous shot to the chin that clung to his beard.
Derek pulled his arm out to replace it with his cock as his knot grew and leaned forward to make out with Peter as he reached his climax. Peter’s rim easily gave way to his knot with each pass as he fucked it in and out, spreading cum around as he filled his uncle’s ass.
After their orgasms completely faded away, they took a break just long enough to catch their breath and re-hydrate, then moved to the king size bed at the head of the playroom. They spent the rest of the evening taking turns milking each other’s prostates with their knots until they were both drenched in cum, sweat, and lube.
For their final round, Derek wore his favorite butt plug for some extra stimulation as he fucked into Peter. He was so wrung out by the end that he faceplanted in Peter’s armpit where the rich pheromones caused his knot to expand rapidly one last time as he came. They fell asleep tangled together while rubbing the mess they had made into each other’s skin.
In the morning Peter was the first to wake up, so he slid down Derek’s body and started licking Derek’s treasure trail. He moved his way up to Derek’s armpits and groomed them while taking in all the pheromones and sex smell from the previous night, getting drunk on the taste and scent.
Derek was still dead to the world even as Peter slipped Derek’s large butt plug out of his ass to be replaced with his dick. He resumed grooming Derek’s armpits as he leisurely fucked into him in the warm morning light, watching as Derek’s cock hardened in his sleep. His nephew was truly beautiful like this. But then again, when wasn’t he?
Derek eventually started to wake up as Peter massaged his muscles and traced their outlines with his fingers. “You slept in quite a while. Stiles is already back to studying.”
“Mmmm,” Derek hummed as Peter thrust into him a bit faster. “How’s he doing?”
He pressed a kiss to Derek’s mouth, “Quite well after the ‘help’ we sent him last night. Although, he did make a saucy comment about us not joining him for bed.”
“We should probably get everything out of our systems today so we can be with him tonight, then,” Derek said as he leaned up to kiss Peter with a bit more intent.
“I suppose so,” Peter sighed as though the prospect of spending the day having sex was a great hardship. He smirked as pulled Derek in by his thighs, lifting his ass up for a better angle to plow into him with a few loud slaps of his hips before reaching his orgasm.
Derek rolled his eyes and flipped them, making Peter let out an “oomph” as he landed on his back on top of the blankets. Derek sensually rolled his hips back, greedily sinking all the way down on his uncle’s oversensitive cock before proceeding to ride him hard to chase his own orgasm.
It didn’t take too long as Peter fucking and grooming him awake had had him leaking precum before he’d opened his eyes. Peter still hissed and gripped his hips from too much stimulation, but let him take what he wanted until he had painted Peter’s abs with cum.
“Want to start with fisting again?” Derek asked, dragging his fingers through the cum on Peter’s chest while still keeping Peter’s cock inside him.
“That sounds like a good idea, especially as my dick is aching right now,” Peter groused.
Derek grinned and carefully got up before helping his uncle to his feet too, “You’ll heal.”
They made their way back to the padded table, Peter laying down on top of it while Derek started lubing up his arm. Peter’s ass was still pretty loose and sloppy, but Derek took his time anyway to explore and stretch him as they recovered from their first orgasms of the day. Roughly ten minutes in, though, and Derek had sunk in up to the elbow and was working on picking up speed.
For Peter, the sensation of being fisted was made more intense by his relatively full bladder as they had not taken a piss break since they started the day before. A particularly good thrust of Derek’s made him let loose a short stream of it that hit his stomach.
Scenting an increase of arousal from Derek, Peter gave a Cheshire grin. “So, that’s how it is. I guess we’ll be getting a bit wetter this morning” he said as he aimed a long, hot stream at his nephew’s chest and watched the golden drops trickle down his abs. “After all, what’s a bit of scent marking between family?”
“If you insist,” Derek said with a smirk as he removed his fist from Peter’s ass and grabbed his dick to return the favor. He started with a shot of piss to Peter’s chin, trailed it over his uncle’s chest and cock, and finished by inserting his still pissing dick into Peter’s hole where he completely emptied the rest of his bladder. He paused after he was finished to relish the feeling of his dick growing hard inside Peter’s piss filled ass.
When Derek did start thrusting, it was at an agonizingly slow pace so as not to spill a drop while still exploring the odd feeling of his cock not being in contact with Peter’s anal walls in the places where they were held round and open by his piss. He couldn’t help but speed up though in order to increase the amount of friction he felt, making some of the hot liquid start to leak out around his dick and down his thighs.
Derek shifted and bent down to grunt-fuck Peter while burying his nose in Peter’s armpit to get the full raunchy scent combination of musky piss and sweat. His inflating knot splashed even more piss out of Peter’s ass as it forced his hole wider on its way in and out before Derek reached his climax and plugged the remaining piss and a fresh load of cum inside.
Peter was not unaffected, but held off on his orgasm and the rest of the piss in his bladder, knowing exactly what he wanted to do with it. He waited out Derek’s knot by heaping his nephew with filthy praise about how thoroughly Derek marked him, speaking directly to Derek’s baser alpha instincts.
“Such a good, strong alpha. You’ve made me so filthy, marking your uncle as your own like real wolves mark their territory. Show me more of how you’re like them; use your rare gift to lick me with that long, slobbery tongue like no one else can, tasting your claim on me” he finished in a purr as Derek pulled out and was splashed with a small stream of piss and cum that had built up.
Derek wasn’t fooled but complied anyway. He smirked knowingly before transforming into a wolf and licking in slow, wet strokes over Peter’s abs, then leapt up on the table to straddle him. He licked between Peter’s pecs and up his throat, both of which his uncle loved showing off in those damn V-neck shirts that could be so enticing.
They didn’t often make out while in wolf form, but with so much lust building between them Derek slipped his long canine tongue into Peter’s mouth, licking inside and battling Peter’s thicker human one.
Peter shivered, not in disgust but from the rush of adrenaline at being so close to a wolf’s powerful jaws and sharp teeth while knowing with absolute certainty he was safe in his alpha’s care.
Backing off to let Peter catch his breath, Derek spent some time sniffing and licking up the heady sweat in each of Peter’s armpits, grooming Peter as Peter had done to him earlier. Human tongues were good enough for this task, but not nearly as effective - or as arousing - as a long, slobbery canine tongue. As a wolf, he also had the boon of further refined senses that enhanced the aphrodisiac effect it had on him.
When he was satisfied, he leapt forward off the table (all the better to give Peter a good look at his heavy balls) and trotted around to Peter’s ass to give him the rimming of a lifetime. He dug in deep to get a taste of his own cum and piss, nearly sticking his muzzle inside Peter’s loose ass, and made Peter gasp by wiggling his tongue around as much as he could. He finished with a long lick up Peter’s straining cock to almost bring him to an orgasm before stepping back to sit with his tongue lolling out.
“Derek, don’t leave me hanging! Fucking tease of a wolf,” Peter muttered before finally getting up to fuck Derek’s muzzle exactly as Derek had been waiting for. It seemed his nephew was determined to make him work for his orgasm this time.
Peter started slow, pushing in past Derek’s lips and over that damn tongue. He flexed his arms above his head to sniff and lick at his freshly groomed armpits while thrusting into Derek’s muzzle with just his hips, then brought them back down to hold Derek’s head so he could go faster. He hissed at the light scrape of Derek’s long canines on either side of his dick as he skull fucked the wolf. The slight bit of teeth didn’t actually hurt, not really, just added a hell of a lot of stimulation.
Derek was quite pleased with himself at making Peter do more of the work this round. Plus, giving blowjobs was so much easier as a wolf thanks to the long muzzle, especially when he opened his jaw a bit wider for Peter to fit both his cock and balls inside his mouth. He couldn’t do that as a human, but as a wolf it was the equivalent of normal deep-throating.
Peter held his cock and balls in Derek’s jaws for a moment, trying not to cum, before he backed out completely. He smirked and gave Derek a “turn around” motion very similar to the one Mufasa gave Zazu before pouncing practice in The Lion King, but with a very different type of “pouncing” in mind.
Peter dipped his hand in the bucket of lube and fingered Derek open. It was odd and yet not to think that his cum was still in there from earlier that morning as well as the previous night. The mind likes to play tricks in making you think the wolf body was separate from the human body, but for a werewolf it was one and the same, just as a muscle remains the same muscle whether it’s flexed or relaxed.
And speaking of relaxed, Derek had gone almost completely boneless; leaning into Peter’s thigh and tail making slow sweeping motions over his arm as he played with Derek’s hole. He worked up to four fingers but didn’t go any farther even though Derek could easily take more. This way he would be loose enough while still maintaining a snug fit.
“Ready?” he asked softly as he petted Derek and removed his fingers. Derek gave a low woof in reply and stood up straight.
With his cock still mostly hard and no longer in danger of cumming too soon, Peter lined up and pressed slowly into Derek’s hole. He was torn between watching his dick disappear into the furry rump and trying to get a peak at Derek’s canine cock poke its way out of its sheath in reaction to being fucked.
But then he was flush with Derek’s sleek black fur that gave way to the soft skin of the wolf’s asshole where his dick was fully enclosed in tight, slick heat. Derek’s bushy tail curled possessively around Peter’s arm as he firmly held Derek’s haunches against his hips, his balls nestled against Derek’s furry ones.
Derek turned his head and gave Peter an impatient look to get him to move and move Peter did, making Derek bark in surprise with the force of the first thrust.
It was a few minutes of fast paced fucking before Peter slowed down to drape himself along the huge wolf’s back, Derek easily taking most of his weight as his arms wrapped around and under to fondle his sheath and lupine cock. Feeling coarse fur along as much of their naked skin as they could was one of the sensations they all favored whether they were having sex or not, so he settled into a series of deep thrusts and grinds while only moving his hips to maintain that contact. Derek certainly didn’t object to either the deep dicking or being hugged closely while receiving it.
Peter let go of Derek’s cock and hugged the wolf’s chest as he shifted into his beta form and let his knot swell, slowly opening Derek’s hole wider and wider on each pass in and out. Even though he wasn’t an alpha, he was still able to channel a little bit of his old monstrous alpha form when he wanted to - and that happened to include making his cock larger than it already was.
Derek got closer and closer to his orgasm as the stretch increased beyond what Peter’s four fingers had accomplished and climaxed as Peter’s knot reached the size of a fist and locked in tight against his prostate. He knotted the air and his cock bounced up and down as it sent rope after rope of cum to the floor.
Peter let go of his own orgasm as Derek’s hole clenched around his dick. As he filled Derek’s wolfy ass with cum, he brought his hand down collect as much of Derek’s cum as his palm could hold and brought it up to his mouth to lick up before offering some to Derek too.
Palm clean, Peter carefully lifted Derek to his chest while they were still knotted and made his way over to the bed. His cock shifted inside Derek’s ass with each step and provided starbursts of pleasure that prolonged their orgasms. Peter carefully laid them down with Derek as the little spoon while they waited for his knot to go down on its own instead of ending it early by shifting back.
As Peter slowly went soft and lost his wolf features, he was careful not to slip out of Derek’s ass. Ready to put the piss he had been saving up to good use, he groaned as he was finally able to relieve himself after holding it in for so long. Some of it leaked out of Derek’s loose hole, matting down more of the fur between them that was already slick with lube.
Even more piss and cum spilled out and helped slick up his hand when Peter replaced his cock with three and then four fingers, but he paid it no mind as there would still be plenty left to plug inside. He grabbed a bottle of prepared J-Lube from beside the bed, squirted a generous amount of it into Derek’s ass along with what piss and cum were left in there, and slicked up his hand properly.
Derek panted in anticipation, his tail thumping on the bed as it wagged. Even as wolves they both loved being fisted.
Peter clucked his tongue and moved the wet tail aside so he could continue fingering him unhindered.
Derek’s rim was soft and puffy as Peter pumped four fingers in and out a few times while his thumb rested in Derek’s soaked fur. Satisfied, he brought his thumb down to join his other fingers and kept them together as he pushed into Derek’s ass. There was a small bit of resistance as he worked past the widest part of his hand, but it easily slid the rest of the way until Derek’s rim slipped over his wrist.
“Your ass is so perfect, whether you’re shifted or not,” Peter murmured into Derek’s fur as he pulled all but the tips of his fingers out, then slowly worked his hand back in again while Derek’s cock rehardened. He wiggled his fingers around, making Derek pant and whine in pleasure as his inner walls and prostate were stroked, and went deeper; grateful for the extra lube he’d added.
Peter drew his hand part way out and paused at the widest part to give Derek’s hole a good stretch, making it bulge obscenely outwards. He used the opportunity to spread the lube further down his arm before pushing in again, this time fitting most of his forearm inside. It was mesmerizingly erotic to watch Derek’s rim as it lovingly gripped his arm, following his movements as he thrust in and out.
Derek was in heaven. This body was just as large as his human one, but the advantage of a longer and straighter anal canal meant deep anal play was actually easier. The straight length also meant his prostate was much easier to stimulate and he felt every change in thickness as Peter’s arm moved in and out; further amplified by being more used to his human form than this one.
It became so much more intense when Peter shuffled backward to straighten out his arm and fit his elbow in, the start of his bicep just touching Derek’s rim. Peter’s hand moved deep inside him as the elbow was teased in and out of his hole, yet it still wasn’t quite enough to make him cum.
The needy whine Derek let out the sixth time Peter sunk his elbow into Derek’s ass was just the signal he had been waiting for. He pulled his arm back enough so he could bend forward and take Derek’s cock into his mouth. Derek came nearly the instant the tip entered his mouth, but he continued sinking down until his cheeks were bulging with Derek’s knot and his face was buried in a furry crotch.
Peter pumped his arm in and out a few more times as Derek’s ass clenched around him, then pulled back until the rim was comfortably over his wrist again. He twisted and flexed his hand a bit to simulate a knot and hummed around Derek’s cock to make him whiteout with pleasure. He had been damn proud of being able to give anyone the best sex experiences of their lives but felt so much more fulfilled now that he was providing it to the few people he really cared about.
When Derek’s brain came back online, Peter had removed his hand from his ass and was back to spooning him. His ass ached a bit, but it was a good sort of ache which faded as he shifted back. “That was amazing,” he said as he turned in Peter’s arms.
“I aim to please,” Peter replied. “I do love you, after all.”
Derek kissed him, long and slow. “And I love you. I think we should get a shower soon, though.”
“Sadly, the allure of marking in the traditional way only lasts for so long before that does become a necessity,” Peter said as he sat up and stretched. “Let’s clean up and then we can get some lunch.”
“And make sure Stiles has some too,” Derek agreed as he let Peter help him up and they walked into the en-suite bathroom for a shower.
There were still times when they argued or infuriated each other, but when it came down to it they both protected the pack in their own ways and knew they could count on each other again. Their bond was stronger than ever, they had a pack, a chosen family, and they were happier than they had been in a long time.