River Song x Thirteenth Doctor x Plus‑Size Black!Reader
You’re halfway back to your room when you hear it—
A low, ragged ohhhh that makes you freeze mid‑step, socks squeaking slightly on the TARDIS floor.
Your high‑hazed brain kicks in slowly:
You tiptoe down the curved corridor, oversized shirt brushing your thighs. The faint weed smell still clings to you, sweet and earthy. You’d been outside on the TARDIS steps ten minutes ago, looking at stars and trying to talk her into just one hit.
“Time Lords don’t get lung damage, Doc! C’mon. It’s relaxing!”
She’d laughed, cheeks pink, hands waving wildly. “I relax loads! I’m very relaxed!” (She is never relaxed.)
But the noise again—broken, desperate—pulls you closer. A door ahead is cracked open, golden lamplight spilling out.
You lean in, heartbeat in your ears.
…and immediately clap a hand over your mouth.
Inside, River’s curls bounce with each thrust of her hips, the shimmer of a black strap harness catching the light. She’s got the Doctor—your Doctor, with that blonde hair falling in her face and her rainbow shirt rumpled—bent over a padded bench. Coat tossed aside, trousers halfway down, her thighs shaking as she claws at the bench, gasping out little half‑choked noises.
“River—” 13’s voice breaks on the name, high and trembling.
“Oh, you sound divine,” River purrs, hips rolling deeper, slower, drawing out another whimper. “That’s it, love, take it. You always take me so well.”
Your knees almost buckle. You shouldn’t be watching. You shouldn’t. But you’re rooted to the spot, heat pooling low in your belly.
Then River’s head lifts. Those dangerous eyes find you instantly through the cracked door.
And her smile blooms wicked.
She doesn’t stop. She tightens her grip on the Doctor’s hip, leans down close to her ear, and loud enough for you to hear murmurs,
“If they could see you now, my darling… the brilliant Doctor, gasping like this while I ruin you.”
The Doctor sobs out a breath, face hidden in the crook of her arm. “R‑River—don’t—”
River tuts, slow and deliberate in her thrusts, and locks eyes with you again.
“They’ve been wandering this ship in those little shorts… do you know how badly we’ve both wanted to feel them between us? Imagine it, Doctor—imagine them right here, tasting you while I—” She punctuates with a sharp thrust that makes 13 yelp.
You feel your entire body go molten, one hand braced on the doorframe to keep upright. Your mind is a mess of holy shit holy shit holy shit.
River’s grin widens. She keeps her eyes on you as she murmurs to her wife, “You’d like that, wouldn’t you? Letting them see how pretty you look when you come apart?”
The Doctor makes a sound that’s somewhere between a sob and a laugh, legs trembling. “Y‑yes— ohhh, stars—”
Not when River’s rhythm quickens, her voice dropping to a growl.
Not when 13’s moans turn frantic, when she shakes apart in River’s hands, gasping, boneless.
You’re still pressed against the wall when River slows, soothing, brushing hair from 13’s flushed face.
“You’re perfect, my love,” she whispers to her.
And then, just before she closes the door fully, River glances back at you. The smile she gives you is lethal. A promise.
Later, you’re sitting cross‑legged on your bed, staring at your ceiling, brain spinning so fast it’s almost funny. Your cheeks hurt from grinning. Your whole body is warm.
The door opens with a soft creak.
River slides in, curls damp now, still glowing with that post‑sin radiance. She leans on the doorframe, arms crossed, lips curved.
“You stayed longer than I thought you would,” she says, amused.
You choke. “I— I didn’t mean— I was just—”
“Oh, sweetheart.” She crosses the room, crouching in front of you. Her fingers rest lightly on your bare knee. Her voice drops low, conspiratorial. “You know we’ve been trying to flirt with you for weeks, don’t you?”
Your breath hitches. “I thought… I mean, you’re married—”
“Mm.” River hums, eyes glinting. “Married, yes. Closed? Not even slightly.” Her thumb strokes over your knee, sending sparks straight through you. “And after tonight? Oh, darling… she’s going to think about you every time she touches herself.”
Your mouth goes dry. “She… knows I saw?”
River’s grin turns wolfish. “Not yet.” She winks. “But I’ll tell her.”
“She deserves to know how lovely you looked standing there,” River says, standing smoothly, brushing her curls back. “Besides… it’ll give her something to think about. Something to look forward to.”
You stare up at her, flustered and aching, as she heads back toward the door. She pauses in the doorway, glancing over her shoulder.
“Wear those little shorts again tomorrow,” she says with a smirk. “And maybe bring that blunt of yours. We’ll convince her yet.”
The door shuts softly, and you collapse back on your bed, burying your face in your hands, giggling helplessly.