Jake Obsesses Over His Sissy Stepsister

I never thought living with my stepbrother Jake would turn into this intoxicating secret, but here I am, spilling it all like a confessional in the dim glow of my laptop screen. I'm Sissy, 20 years old, and after a year on HRT, my body's transformed into this voluptuous dream—soft, budding C-cup breasts that strain against my lacy bras, wide hips that sway with every step, and a plump ass that fills out my thongs perfectly. My girlcock is still there, tucked away most days, but it's part of what makes me feel so alive, so feminine. Jake's 22, all lean muscle from his gym obsession, with that chiseled jaw and messy dark hair that makes my stomach flip. We've shared this cozy two-bedroom apartment for six months now, ever since our parents split and we needed a cheap place near campus. At first, it was just sibling vibes—step-siblings, technically, since our folks married when we were teens—but lately, the air between us crackles with something forbidden and electric.

It started innocently enough, or so I told myself. One afternoon, I was in my room changing after a shower, the door cracked because who expects a stepbrother to barge in? I stood there in just my panties, my full breasts perky and nipples hardening in the cool air, running my hands over my curves, admiring how my estrogen had sculpted me into this hourglass goddess. The mirror reflected my long auburn waves cascading down my back, my plump lips glossed pink. Then, bam—the door swings open. Jake freezes, his eyes locking onto me like a magnet. "Shit, Sissy, sorry—" he stammers, but he doesn't look away. His gaze traces my body, lingering on the swell of my breasts, the dip of my waist, the way my panties hugged my thickening thighs. I could see the bulge twitching in his jeans before he finally tears himself away and bolts.

From that moment, everything shifted. He'd steal glances across the breakfast table, his fork pausing mid-air as I bent over in my yoga pants, my ass cheeks peeking out. In the kitchen, his hand would brush my lower back "accidentally" when reaching for a glass, sending shivers up my spine. I'd catch him staring at my cleavage when I wore my low-cut tops, his cheeks flushing as he adjusted himself discreetly. I teased him back, of course—wearing shorter shorts around the house, letting my robe slip open just enough to flash a nipple. The tension built like a storm, awkward silences broken by lingering touches: his fingers grazing my thigh when we passed on the couch, my foot nudging his crotch under the dinner table. I knew he was obsessed with my curves, and god, it made my girlcock stir every time. By the end of the week, I was wet-dreaming about him, waking up with my panties soaked.

That late-night movie session was the breaking point. It was Friday, parents long gone on their separate vacations, just us in the living room with takeout boxes scattered and some dumb action flick flickering on the TV. I'd changed into my favorite sleep set—a silky pink babydoll that barely covered my ass, the lace trim tickling my sensitive skin, my breasts spilling out the top. No bra, nipples poking through like invitations. Jake was in sweats and a tee, sprawled on the couch, but I saw the way his eyes devoured me when I flopped down next to him, our thighs pressing together. "Comfy?" I purred, crossing my legs so my nightie rode up, exposing the smooth expanse of my inner thigh.

Halfway through the movie, the tension snapped. Jake shifted, his hand landing on my knee—deliberate this time. "Sissy," he whispered, voice husky, "I can't stop thinking about you. Ever since I saw you changing... fuck, your curves. They're driving me insane. Those tits, that ass—I crave them. I want to touch you, taste you. Please." His confession hung in the air, raw and needy, his hand sliding up my thigh, fingers trembling as they traced the edge of my panties. My heart raced, heat pooling between my legs. I turned to him, our faces inches apart, and grinned wickedly. "You have no idea how long I've wanted this, big bro."

I leaned in and crushed my mouth to his, tasting the salt of his lips as his tongue slid greedily against mine. Jake’s hand shoved higher, cupping the hard heat of my girlcock through the thin lace of my panties, squeezing until I whimpered into the kiss. He broke away only long enough to growl, “Fuck, Sissy, you’re already dripping for me,” then yanked the babydoll up over my head in one rough pull. My bare breasts bounced free, heavy and sensitive; he latched onto the right nipple immediately, sucking hard while his free hand mauled the left, pinching and rolling until my back arched off the couch cushions.

I fumbled at the waistband of his sweats, shoved them down his hips, and wrapped my fingers around his thick cock. It pulsed hot and heavy in my palm, already leaking. Jake groaned against my tit and thrust into my fist. “Yeah, stroke that—make it nice and wet for your tight holes.” I spit into my hand and worked him faster, twisting over the swollen head while he bit and licked every inch of my chest. His fingers hooked my panties aside, brushing the slick head of my girlcock before sliding lower to tease my puckered hole. I was soaked back there too, aching.

“Please, big bro—fuck me,” I begged, lifting my hips. He flipped me onto all fours on the wide couch like I weighed nothing, yanked my panties down my thighs, and shoved two spit-slick fingers straight into my ass. I cried out, pushing back, feeling them scissor and stretch me open while his other hand reached under to fist my dripping girlcock. He pumped both ends of me in matching rhythm until I was panting and leaking onto the cushions. Then the fingers vanished. The blunt head of his cock pressed against my rim.

Jake sank into me in one long, steady thrust, burying every thick inch until his hips slapped my plush ass. The burn melted into raw pleasure; my walls clenched around him and I sobbed his name. He didn’t ease up. He fucked me hard and deep right away, hands locked on my waist, yanking me back to meet every brutal stroke. The wet slap of skin filled the living room, mixed with my high, needy moans and his low curses. “Goddamn, this ass was made for my cock. Look at these curves—those tits swinging, that fat little girlcock bouncing. You’re my perfect little sissy whore.”

I reached back and spread my cheeks wider for him, letting him watch himself disappear into me. He spanked one jiggling globe hard enough to sting, then the other, the sharp crack making my girlcock jump and drool. When he leaned over my back, chest plastered to me, one hand snaked under to stroke me in time with his thrusts. His fist was tight, thumb swiping the wet tip on every upstroke. Pressure coiled low and fierce. I shoved myself onto him harder, chasing it.

“Come for me while I fill this hole,” he ordered against my ear. That was all it took. My orgasm ripped through me; my girlcock pulsed hard in his grip, thick ropes of cum painting the couch and my own trembling thighs while my ass milked his cock in fluttering waves. Jake roared and slammed deep one last time, flooding me with hot spurts that overflowed and dripped down my crack. He kept rocking through it, grinding every last drop inside, until we both collapsed forward in a sweaty heap.

We stayed locked together, breathing hard. He kissed the back of my neck, gentler now, hands stroking the soft curves of my hips and belly. Slowly he eased out; I felt the warm rush of his cum following, and I clenched to keep as much as I could. Jake rolled us onto our sides facing each other on the ruined couch. His fingers traced my swollen lips, then down to my spent girlcock, petting it softly. “That was better than every dirty thought I’ve had about you,” he murmured. I smiled, lazy and satisfied, and draped a leg over his hip so we stayed pressed close.

“Good,” I whispered, “because we’re nowhere near done. This apartment’s ours all weekend.” His cock twitched back to life against my sticky thigh. I laughed low and kissed him again, slow and deep, already sliding my hand between us to guide him home once more. We lost track of how many times he took me that night—on the couch, bent over the arm, me riding him reverse so he could watch my ass bounce and my girlcock slap against his stomach. Each round ended with him buried to the hilt, pumping me full while I came undone around him. By dawn we were a tangled mess of limbs and cooling sweat, his arm locked around my waist, my head on his chest. I drifted off to the steady beat of his heart, already craving the next time he’d look at me like that—hungry, obsessed, and completely mine.