[M4F] Girlfriend Forces My Taboo Confession

My girlfriend is petite perfection — barely 5’2”, slim and toned, small perky tits, tiny waist, tight little ass that fits perfectly in my hands. She’s playful, confident, and filthy when we’re alone.

My famous younger sister is almost her mirror: even tinier frame, delicate features, soft small breasts, narrow hips, the same innocent-yet-irresistible petite build that turns heads everywhere. The world knows her from that massive fantasy series, where her barely-there scenes leave little to the imagination.

Maybe that’s why I fell for my girlfriend so hard — subconsciously picking someone who looks just like her. I never admitted it out loud. Never wanted to face it.

But she notices everything.

During one of our movie nights, we put on my sister’s latest project. A nude scene flashes — her petite body glowing on screen, vulnerable and breathtaking. My cock twitches hard against my girlfriend’s thigh as she straddles me. She freezes, then smirks.

“You just got so fucking hard watching your little sister.”

I stammer denials — “It’s the scene, anyone would…” — but she grinds down slowly, whispering, “Liar. You’ve been hiding this.” Her hand slips between us, stroking me through my boxers while the on-screen version of my sister moans.

“Tell me the truth,” she breathes against my ear. “Admit you think about her tiny body like this. About fucking her the way you fuck me.”

I fight it — head shaking, words tumbling out in weak protests — but my hips buck up involuntarily, betraying me. She keeps pushing, teasing confessions out of me mid-thrust:

“She’s so small… just like me…”

“Bet her pussy would feel even tighter…”

“You want to breed her, don’t you? Fill that perfect little sister body…”

She’s relentless, forcing the words from me until I’m gasping admissions while buried inside her.

Now my sister’s coming to stay — crashing in our guest room for weeks. My girlfriend’s eyes sparkle with mischief every time we mention it. She wants more: “accidental” brushes in the hallway, late-night hangouts where she grinds on my lap with my sister dozing nearby, coaxing me to crack wider open.

Slow-burn. Long-term. Detailed, literate replies.

You play both: my eager, teasing girlfriend who loves breaking my denial, and my shy/innocent famous little sister (reluctant/curious if things escalate). Emphasis on psychological tension, forced confessions during sex, the lookalike vibe, risky house teases, breeding fantasy whispers, light sleep-adjacent buildup.

Kinks: brother/sister incest (famous petite little sister), lookalike girlfriend, denial → reluctant confession, teasing/coaxing, grinding, groping, outercourse, risky proximity, breeding talk, FFM potential

Limits: violence, gore, smells, toilet, snuff, animals, food play