Work Text:
Caleb’s mind has been drifting into a darker and darker place ever since he’s been spending the summer with his younger sister.
Both of you have decided to spend two weeks of your break at your grandma's, as a chance to wind down from your rough university studies and to catch up with one another.
For the first couple of days it has been nothing but blissful for Caleb, getting to hear you ramble about school, new friends, parties, drama. Listening to you complain about how you had to start doing things for yourself since your big brother wasn’t there to do it for you. And on top of that…
Boys.
Caleb’s eyebrow twitches at the thought. The mere image of seeing his sweet baby sister kissing–no, holding another man’s hand has him seeing red.
Of course, none of the men you’ve met have gotten very far with you, he made sure of that.
But the urge he has felt over the past week has him doubling over in the safe confines of his bedroom, cock throbbing in his boxers.
“Are you even listening to me?”
Caleb turns towards you, nodding his head. “Yeah, you need your shirt by Friday, right?”
“Yup,” you reply. You’re enjoying the ice cream cone that he bought you, the melting dessert running down your fingers as you lick the sides. “Can you do my laundry for me?”
“Of course pips,” Caleb stretches, averting his eyes. “Leave it to me.”
–
The ceiling fan is all Caleb can hear as it fights against the humid air. He lies on his back in nothing but a t-shirt and boxers, one arm thrown over his eyes and the other resting on his stomach. He’s been staring at the same crack in the wall for forty minutes.
The house is quiet. Grandma went to bed at nine, same as every night since they were kids. The floorboards still creak in some places, the AC unit in the room next to him rattles as it usually does.
But nothing is the same. Not this summer.
Caleb’s jaw tightens as he shifts on the mattress, the friction of cotton against his cock making him hiss through his teeth. He’s half hard. Has been for the past three nights, ever since you and Caleb went to the pool together.
He spent that night in the shower, palm braced against the wet tile, jerking himself raw with the water scalding down his back. He imagines your body beneath him, back arching and lips parting to moan his name. Moaning for her big brother. Your pussy clenching around his cock, squeezing him tight as he makes you cum for the hundredth time.
He came so hard he nearly put a fist through the wall. And then he did it again the next night.
And the night after that.
Tonight, he’s out of restraint.
Caleb sits up, running a hand over his face and drags his palm down his jaw. When he opens his eyes, the room is still dark and you’re still sleeping a room away, wearing that tanktop that barely fits you tonight because it was “too hot, gēge, I’m dying.”
He saw you in it when you said goodnight. The thin straps over your shoulder, the fabric hugging your curves a little too tightly, barely containing your breasts. Your nipples stiffening from the constant friction of the shirt, forming peaks that he can see so, so clearly.
You’re not a kid anymore.
Despite the fact that he knows you can survive without him now, capable of taking care of yourself, he can’t help but think of the sweet girl he grew up with.
He stands, letting his feet touch the cold floor. Not bothering with pants he exits out his bedroom and into the hallway, avoiding the creaks in the floorboards. He stops outside your door.
There’s a sliver of light underneath. You’ve always slept with the lamp on ever since you were little, something he used to tease you for. He would leave his own door cracked just in case you felt the need for your big brother to protect you, letting you slip under the covers of his bed.
Caleb knocks gently, before opening the door.
You’re curled on your side, hand tucked under your cheek. The lamp casts a warm glow over your face, a mix of the lighting and your relaxed features making you look younger and less stressed.
The tanktop you’re wearing has ridden up, the hem bunched below your soft tits, exposing the skin of your stomach. Caleb lets himself look, his body on fire.
He shuts the door behind him, and you slowly start to stir. You make eye contact with him, eyes hazy with sleep and unfocused. “Gēge? What time is it?”
“Late,” he replies, voice rough. He clears his throat. “Couldn’t sleep.”
You hum sympathetically, patting the empty space beside you. “Bad dream?”
“Yeah.” He sits on the edge of the bed, the mattress dipping under his weight as he lies on his back. You shift closer, seeking his warmth, the way you had done since you were kids. The same way you always did, trusting him. Fuck, his cock hurts.
“You’re tense,” you murmur. You press your head to his chest. “Your heart is going so fast.”
“Mhm.”
The look you give him makes him ache, wondering if you understand the tension between the both of you right now, if you have the vocabulary to describe it.
“Big brother? Are you okay?” Your voice is soft, almost uncertain. “Gēge–”
“Shh.” Caleb presses his forehead to yours, eyes closed and breathing ragged. “I’m going to show you something, sis. Something that feels good, but you have to trust me.”
Your fingers clutch onto the fabric of his shirt, not pushing him away. Good.
“I always trust you.”
Caleb opens his eyes. You’re looking at him, wide-eyed, uncertain, but willing. He knows you don't know what you’re agreeing to, doesn’t understand that the brother you trust is about to take something from you that you can never get back.
With a shaky breath Caleb leans forward, barely pressing his lips to yours. He feels you freeze in his hold, your breath catching against his mouth. But you don’t push him away regardless.
He pulls back, looking at you. Your eyes are wide, confused in a way that makes his chest ache and his cock throb at the same time. There's a glossy sheen to your lips. He wants to kiss you again.
“Big brother, what was that for?” He doesn’t answer, and instead cups your jaw, thumb tracing your cheekbone as he kisses you again.
This time his tongue slides along the seam of your lips, coaxing, asking for entry. You make a startled, soft sound, letting your mouth open under his. Caleb’s heart tightens as he watches your instinct win over your confusion, and trust win over your fear.
The only thing he can hear in his mind is mine. Caleb knows you’ve never been kissed before, nobody ever getting the chance to explore your mouth with their tongue. Not even a peck. It makes him keen with possessive pride.
Caleb shifts his weight and rolls over you, settling between your thighs. You look up at him from beneath, eyes half-lidded, trusting, and pliant.
He could take you right now. Could shove your shorts down, pushing himself inside, take what he’s been dreaming about every night. You wouldn’t stop him, knowing your big brother would never hurt you.
But he wants you to know. To know what’s happening, even if you can’t explain it. Caleb wants you to choose him, the way he’s already chosen you.
“Baby sis,” he rasps. His fingertips intimately trail down your throat, over your collarbones, and down to the hem of your tank top. “Can I take this off?”
Caleb watches you swallow, chest rising and falling with each breath. Your nipples are hard beneath the fabric.
“Yes,” you lick your lips. “Will you explain what’s happening?”
He freezes, the innocence in your voice stopping him. “I’m going to make you feel good, baby sister.” He hooks a finger under the strap of your top, pulling it down your shoulder. “The way only I can. Will you let gēge do that for you?”
“Yes, I trust you.” It’s said without hesitation, the way you’ve said it a thousand times. When he taught you how to ride a bike, walked you to school.
Caleb pulls the strap down on the other shoulder. The top slides, pooling at your waist, exposing your perfect, soft breasts. You make a small sound, out of embarrassment maybe, your hands coming up to cover yourself.
“No.” Caleb catches both your wrists with one hand, pinning them above your head. “Don’t hide from me, let big brother see you, sis.”
Caleb glances down to see a wet patch that has seeped through your panties, staining your shorts. Fuck, he’s spent too many nights alone with your panties. Compared to that, this is heaven.
“Gēge, I’m scared.” Of course. Caleb knows he has always kept you sheltered.
“I know.” Caleb kisses your forehead, then the tip of your nose, before settling for the corner of your lips. “I’ve got you, let big brother take care of you.”
You tilt your head up, as if giving a silent offering.
Caleb groans, low and rough as he lets his tongue sweep around your mouth, tasting you. Your arms wrap around him, clinging to the fabric draped across his back.
He rolls his hips against you, letting you feel what you do to him. The thick outline of his cock presses against your thigh, your eyes going wide when you feel it.
“Is that…?”
“Yeah,” he breathes out. “ That’s what you do to me, lil’ sis. Every time you walk by in those little shorts, or whenever you call my name.” He grinds against you, slowly introducing you to what he has hidden beneath his boxers.
“I didn’t know,” you whisper. “I also didn’t know it–we could be like this.”
“We can,” Caleb assures you, tugging your shorts down. He slides them down past your knees before tossing them off the bed, landing somewhere in the dark.
The panties you’re wearing are cute, comfortable, with a little bow in the centre. Ah, fuck. He’s aching to be inside you, to taste you.
“Do you want me to touch you?”
You nod. “Aches.”
“Where?” Caleb rubs circles on the elastic, watching you squirm. “Use your words like a big girl, lil’ sis.”
You make a frustrated sound, so achingly familiar he almost laughs.
“Touch my pussy, big brother. Please.”
The dirty words that fall from your mouth send a surge of heat through him, so intensely he sees white. His hand slides down to cup you through the cotton, groaning at the wet heat of you.
Your back arches and your hand flies to his wrist, holding him in place. Caleb presses down on the damp fabric, rubbing circles slowly. “Good, sis?”
“Yes,” you tremble, stuttering over your words, wrecked.
Caleb pulls the waistband of your panties, letting them dangle from one knee. You’re bare beneath him now, spread and innocent.
He pulls his own shirt over his head, watching your eyes trail his sculpted chest down to the dark hair near his lower stomach, where it disappears into the waistband of his boxers.
Caleb then pushes his boxers past his hips, revealing his cock. It springs free, thick and aching, the head already slick and beading with precum.
Your lips part. “Is that… going to fit?”
Caleb laughs, wrapping a hand around himself as he strokes once, slowly, watching you watch him.
“Don’t worry, baby sister.” He leans down, letting his length press against your thigh, hot and heavy. “Big brother will make it fit in that cute lil’ cunny.”
You swallow as Caleb lines himself up. The head of his cock presses against the tight, impossibly small entrance to your cunt.
“Tell me if it hurts and I’ll stop.”
The first inch draws a sharp cry from your lips, fingers clutching his shoulders as he holds himself there.
“Big brother,” you whimper. “It hurts.”
“I know, you’re taking me so well. Your pussy is stretching so nicely around your big brother’s cock.” Caleb presses a kiss to your temple.
With a nod of your head, Caleb slides in deep until the entirety of his length buries into your pussy. Each thrust is deep, the bed creaking with the slow rhythm.
As soon as moans start to tumble past your lips, Caleb takes it as a sign to quicken his pace, driving into your pussy harder. The clenching of your tight cunt makes Caleb stutter, the pace of his hips becoming rough and harsh.
“You like that, baby sis?” He pounds into you, hitting that spot over and over. “You like your big brother fucking you? No one else is ever going to be able to feel this. You’re too good for them, anyway. Always have been.”
“H-huh?” Caleb feels you clench around him tighter at his words.
“Fuck, I’m not even wearing a condom,” he groans as he ruts into your warmth. “Letting your big brother fuck your cunny raw.”
“Yes, gēge,” you barely form sentences, eyes rolling back. “I don’t–something feels funny…!”
“Cum for me,” he rasps, reaching deep to slide against your sweet spot. “Cum on your big brother’s cock, let me feel you.”
Caleb feels you flutter around him before you come undone. Your back lifts off the mattress as you reach your climax, walls milking his slick length as he continues to fuck you into overstimulation.
“I’m gonna cum,” Caleb stutters, hips pushing as deep as he can. “Gonna cum in your womb, okay lil’ sis? You’ll let me, right? Can I leave it inside of you? Let your big brother fuck his babies into you?”
You nod and whine in overstimulation, squirming beneath him. “Yes…! Please, inside, gēge…!
Biting his bottom lip at your filthy words. Caleb follows you over the edge, burying himself deep inside you and spilling into your warm cunt with a groan.
He stays there for a second, savouring the feeling as his cock pulses and softens in your tight haven. The only sounds you can hear are heavy breathing and the AC rattling. Somewhere down the hall, your grandma sleeps, oblivious.
Caleb presses his lips to your hair. “Mine.”
“Yours, gēge.” You’re boneless beneath him, curled against his chest. He holds you through the night, enjoying the warm hold your cunt offers him as you sleep.
In the morning, he’ll have to face what he’s done. But for now, he lets himself have her.