#is this blackcest.

[mrstellmeafuckingsecret]

sirius black's hear me outs: fleamont potter, euphemia potter, hephaestus, lyall lupin, the voice that says "divine" on candy crush, peter's mother, uncle alphard, velvet (the texture...), florean fortescue, the bloody baron, the entire concept of titration, cold showers

[prettybabybaby]

rating: 18+. mdni.

pairing: stepbrother!sirius x reader x stepcest!regulus

content: step/incest, sirius and regulus kiss. (don't like, don't read!)

your brothers had always told you that it wasn't weird. it's what siblings do. why are you making something so innocent seem taboo? so disgusting? so wrong?

"it's not like we touch each other anymore," sirius says, his fingers gently tucking your hair behind your ear. the lilt in his voice is familiar—it's the tone he always uses to get what he wants. "they're just kisses. you kiss mother, don't you?"

"on the cheek," you mumble, your gaze drifting from sirius's face, fixing on the vase of flowers you can't quite identify, focusing on the delicate white petals. "mary said it's not right to kiss on the mouth."

regulus interrupts with a small scoff, "of course she'd say that. why are you listening to her? she doesn't have her own siblings, does she?"

you shake your head lightly, blinking up at him, "no, but-"

"but what? there is no but." regulus lets out a disappointed sigh, the sound making your eyebrows furrow in concern, your fingers wrapping around his wrist. "we haven't seen you all day, and you can't give us a little kiss?" regulus's voice takes on a softer edge, "you really think we would make you do something bad? you think so lowly of us?"

sirius sighs in annoyance when you don't respond, the sound louder than necessary. his hand grasps regulus's strong shoulder, giving it a shove. regulus then faces your older brother, grimacing when sirius gives him a teasing raise of his eyebrow. he grips his chin, pulling him in for a light peck. regulus's hand then lowers to curl around the side of sirius's neck, his lips parting to permit sirius's pink tongue access to his mouth as they kiss languidly. familiarly.

sirius lets out a pleased groan, nibbling regulus's lower lip as he pulls away. "see, reggie and i kiss, too. did you think that was gross?"

you shake your head, trying to ignore the discomfort in your lower belly, "no..."

sirius smiles at you, his hands ruffling the top of your head before he leans down to give your lips a chaste kiss. your cheeks heat a little, always feeling a little shy in moments like these.

"there's a good sis..." regulus grins, his eyes betraying his anticipation. his slender finger taps his lips, "come now, give me my kiss."

[thistlecatfics]

never underestimate the power of a long, enthusiastic comment on a slowly updating longfic

[maladaptivewriting]

saw a tiktok comment that called sirius/regulus an “unrealistic ship” which is both hilarious and weirdly not even accurate given their family history

[thatloveislikea-star]

At @brighteststarz request, here are some starcest recs!!

These are just a few of my favorite complete fics, I ran out of steam because I read so much so I might do another list later 😂 a lot of these authors have WIPs that are really amazing, so check those out if you like to follow along

An absolute classic, Want, by Saras_Girl

So good, really interesting family dynamics in Rapture on the Lonely Shore by @tenrousei-kuroi, check out their other starcest too! Another one I love of theirs is Capacious as the Sea

The Mind of Madness by phantasmaraneae is so good I’ve read it so many times

Really really hot, includes James, Little Lion by @tracingpatternswrites

I thought family planning by heated_mausoleum was funny

Heat wave by heartshapedbathtub is one of the hottest things I’ve ever read, definitely read it if you like bunny stuff, they’ve written a few more fics too

Constellations series by Evandar, has two fics, both so good, also Toujours Pur is really sweet

Winner Takes All by @the-invisibility-bloke, it’s hot, it’s funny, it’s charming, it’s perfect

Pretty much everything by @faeries-withspirits , but some favorites are Cherry Waves, Morning Glory, Starbursts (bring me back to life), Down the black hole of my lust I descend, Secret Shows in Shower Stalls. Definitely check their other fics out if you like celestial quad (reg/siri/rem/james) also their WIPs are so good

@thepsychiatristgirl exclusively writes bangers, like And All Was Well, my pussy tastes like pepsi cola (my eyes are wide like cherry pies), and speak in tongues (til you listen). That last one is celestial quad, it’s just too good to omit

Baby, it’s cold outside by @andwaitforthespark is so so so good, their WIPs are amazing, and the house always wins only has one chapter left!

@melissamwrites is one of my favorites, especially Black Holes, please check out their other works, especially their WIPs, especially Wormhole (though it is celestial quad and not just starcest) ALSO they make podfics!!! Check those out for sure!

Underneath the mistletoe by Sirci is one of the sweetest starcest fics ever, they have some other really good fics you should check out!

I love JBlackMalfoyRosier’s smutty little Blackcest series, if you like infidelity, it’s for you!

constellations, collisions, and other ways to say love by @matthewfairhoe is a brilliant two-parter

The Arrangement by rattlesnake_black, technically its wolfstarcest, but the dynamic between Regulus and Sirius is gold, and Remus is a hot bonus

@cassetteinability has some amazing fics, like All night long, need, sweet stars, Friends and brothers and lovers (take care of me) that last one does have James involved

Make Your Dreams Come True by @goldenbi is so hottttt

[crucioslut]

Bellatrix/Sirius is one of if not the hottest hp pairing and we all need to take a moment to really think about that and appreciate it because... wow. That dynamic got me in a choke hold

[siriusblackdevotee]

Warning: Blackcest

prongsfoot making their partners jealous? Old.

Moonwater making their partners jealous? Overused.

Wolfsun making their partners jealous? Boring.

Now, the black brothers acting borderline incestuous to make their partners jealous? New!! Attractive!! Rare!! Fun!!

[girlboysam]

it’s so hard being so proud of something i’ve written but i can’t show anyone because it’s an incest fanfiction

[wolfpants]

a light that never goes out | a sirius/harry/draco fic

A Light That Never Goes Out | E | 6.2k Sirius/Harry, Sirius/Draco/Harry

a birthday fic for @citrusses!! 🍋 happy birthday lor, you wonderful, beautiful human. I made you porn. Thank you so much to @hoko-onchi-writes for the beta and @getawayfox for the cheers, you absolute darlings!

Tags: EWE, POV Sirius, past Wolfstar, hinted Prongsfoot, minor Draco/Others, de-aged Sirius, age difference 31/21, memory issues, timey wimey, Department of Mysteries, Sirius lives, road trips, Grimmauld Place, Wiltshire, Harry has long hair and a nose ring, Sirius's tattoos, Draco in the Muggle World, Draco has a summer job at a farm, smoking, scent kink, UST, unresolved romantic tension, semi-public sex/sex in a loo, blow jobs, the tiniest hint of daddy kink, dirty talk, cousin incest, godfather/godson, hotel room sex, hand jobs, hand kink, finger sucking, kissing, anal fingering, anal sex, rimming (brief), threesome

Sirius returns from the veil five years after he dies and five years younger than he was when he fell through it. When he and Harry decide to escape the dreary confines of London and Grimmauld Place in search of somewhere where they can breathe, they bump into someone completely unexpected.

Two eyes that look like his two eyes stare back at him from the rearview mirror. Sirius clears his throat and directs his squint ahead, out the window instead. “Have you eaten?” Harry asks Draco, clipping his seatbelt in. Sirius stretches forward to fiddle with the buttons on the radio. They’re all shiny and fancy, nothing like the ones in the old Mini Lily used to drive. He has no idea what he’s doing, flicking through a jarring assortment of stations. Harry throws him a distracted smile and twists around to address their interloper in the backseat. “Only, we were thinking about looking for a pub for dinner,” Harry says. Sirius looks back to the mirror, waiting for Draco’s reaction, spotting a pink flash of tongue as Draco licks the top corner of his lip, staring at Harry across the cramped space. “I’m hungry,” he says, and his gaze shifts, briefly, to Sirius.

a light that never goes out on ao3

[twistedstarsintertwined]

getting into a new fandom and seeing two siblings with an enmeshed codependency like oh no here we go again

[prettybabybaby]

alr let’s get nasty and disgusting w it: Reggie and step sister!reader 69ing, with reader underneath Reggie, holding him open for Sirius who is absolutely demolishing his hole

rating: 18+. mdni.

pairing: stepbrother!sirius x reader x stepbrother!regulus

content: incest, stepcest

note: sirius and regulus engage in incest. don’t like, don’t read!

it’s a little embarrassing to have regulus’s nose brush so close to the quickly dampening apex of your legs. the tip nearly delving between your wet folds, his mouth panting against your throbbing clit between his lips. his deep inhales of your heady scent making you want to squirm. but you don’t. you can’t. regulus is too heavy.

your eyes stay glued to the sight before you, regulus's leaking cock swinging above your face, occasionally catching on your lips for you to suckle at the endless beads of precum, sirius's taut balls repeatedly slamming against regulus's reddening backside.

"oh... merlin, reg..." sirius hisses under his breath, his voice deep and velvety as he fucks into regulus eagerly. you feel regulus grunt against your pussy, his tongue poking out to lick your swollen clit. you moan softly, feeling your hips buck upwards, his nose dipping between your folds, your juices likely smearing across his flushed skin.

“j-just… h-hurry up…” regulus pants, the octave of his voice giving away his arousal, “she… she gets the point.”

sirius scoffs, pressing his hips into regulus further, “tighten up then, would you? I haven’t loosened you up already, have I?”

regulus makes a noise you know too well, a groan of embarrassment as he struggles to come up with a retort for sirius’s words. sirius chuckles, moving his hips rhythmically again, the squelch of his cock slamming into regulus’s tight hole growing faster and louder.

regulus pants against your pussy, his impending orgasm making his balls tighten and his tip trickle beads of his cum. he rubs his face against your cunt, smearing your wetness across his face, breathing you in and mouthing you with increasing ferocity as sirius ruts his hips faster, harder, deeper. he lays a wet kiss to your mound, “you’re next, y/n. are… mmph… are you going to take me well like I’m taking sirius?”

[cassetteinability]

@microcest / @macrocest prompt: “that isn’t mine” / 621 words / tw incest duh

also added to ao3 here

“What is…” Sirius slid his leg back and forth between his sheets again, his foot catching on a stray piece of fabric again. He hooked it over his toes before dragging it up to the opening and transferring it to his hand.

It was a pair of boxer briefs, green with a grey waistband, and definitely not Sirius’.

“Regulus!” Sirius called, not wanting to get out of bed, and knowing his younger brother was still awake in his own bedroom. “Reggie, come here!”

“What?” Regulus asked as he stepped into the doorway, expression and tone equally bored. He was dressed in nothing but a pair of pajama pants, a book in his hand with his index finger squished between the pages to hold his place.

“Why are your underwear in here?” Sirius asked, holding up the offending article of clothing to show Regulus. There was a damp spot at the front, dark and stiffening, as if Regulus’ cock had been leaking at the tip before he finally kicked them off, like maybe… “Did you fuck someone in my bed?”

Sirius willed his heart rate not to spike at the visual, silently begging his own dick not to grow hard at the thought of his brother writhing around in the exact spot he was currently laying in.

A blush crept up Regulus’ cheeks at the accusation, but he shook his head all the same. “No, Sirius,” he said, tone suddenly patronizing. “I didn’t fuck someone in your bed.”

Sirius looked at the underwear in his hand, thought about the way they had so clearly been pushed off under the covers in a fit of rushed desperation, and wondered if Regulus had left them for Sirius to find, or if he had simply forgotten them.

“Did you—” Sirius felt his voice break and paused to take a deep breath to steel himself. “Did you jerk off in my bed, Reggie?”

Regulus let out a soft, embarrassed laugh, looking away from Sirius’ gaze. “Of course not, Sirius.” The words were soft, devoid of emotion, and clearly a lie. Regulus wasn’t trying very hard to hide the truth of what he had done.

“Why in my bed?”

“It smells like you,” Regulus replied, his blush spreading further down his face and across his bare chest, but there had been no hesitation in the words.

Oh fuck.

Sirius clenched his eyes shut and dragged in another deep breath. His heart was racing, even as he felt all of his blood rush to his cock at the insinuation.

“You think about me while you touch yourself?” Sirius asked, opening his eyes to look back up at Regulus. He knew his own pupils would be blown wide, lust-crazed and desperate, but it was Regulus that had started this. It was Regulus’ desperation that had led Sirius to realize the thrumming need under the surface of his skin, and Sirius knew Regulus wouldn’t reject him.

Regulus sucked his bottom lip into his mouth and nodded his head. “I can only come when I’m in your bed.”

Regulus could only finish when he felt close to Sirius, when he was surrounded by his scent and his belongings? What would Regulus’ orgasm be like if he came with Sirius in the bed with him?

“Show me,” Sirius said, tossing the underwear to the side and scooting over to make room for his brother. “I want to see your pretty face when you come on my sheets.”

Regulus’ breath audibly hitched. He tossed his book onto Sirius’ dresser before stepping further into the room, all bashfulness just as forgotten as the page he had been reading.

Regulus grinned, a sultry, sexy thing, before sliding his pajama pants down his legs and kicking them off to the side.

“Make me, Siri.”

[maladaptivewriting]

“i don’t hate on ships unless they’re illegal or incest” boringggggg, who caressss

[thatloveislikea-star]

My FBI agent is so tired of me hitting refresh on the starcest tag on ao3

[mrstellmeafuckingsecret]

hope you guys know i interact w starcest in a "incest 🫵🏼😟!" way and not in a "incest 🫵🏼😏!" way

[blackcestfest]

Blackcest Fest will be returning for round three 🖤

November 2025-March 2026 with specific dates to be announced

toujours pur