I thought we were done for the night.
My cock was still twitching, half-hard and glazed with our mixed juices, when Mia's husky whisper floated up from the bottom bunk twenty minutes later.
"Alex… I can feel your cum leaking out of me every time I shift. It's driving me fucking insane."
The ladder creaked. She was climbing again.
This time she skipped reverse cowgirl entirely. She swung a leg over and straddled me face-to-face on the narrow top bunk, knees planted beside my hips. Her tank top was gone—full, heavy tits swaying, dark nipples stiff and begging. The black thong stayed shoved to the side, her pussy puffy and shiny with the thick creampie I'd already pumped inside her.
"Round two," she breathed, guiding my cock back to her sloppy entrance. "And this time I'm facing you so I can watch your face when you lose it inside me again."
She sank down in one smooth, greedy glide, taking every inch until her clit ground against my base. We both hissed. She was even slicker now, hotter, the second entry making filthy wet schlick sounds that echoed way too loud in the silent room.
Mia started riding—slow, deep rolls that made her tits bounce inches from my mouth. I grabbed them, squeezing hard, pinching her nipples while she bit her lip to stay quiet.
"Fuck… you're still so hard," she panted, grinding deeper. "You love knowing your stepsister is walking around full of your load, don't you?"
I groaned under my breath. The bunk frame squeaked with every thrust.
She reached for the metal headboard to steady herself—and her fingers snagged the edge of my nightstand drawer. It slid open with a soft rattle.
Mia didn't notice at first. She was too busy bouncing, chasing her next orgasm. But then her hand brushed fabric inside. She froze mid-ride, eyes narrowing.
Still impaled on my cock, she reached in and pulled out a single pair of panties.
Sophia's.
Black lace. Expensive. And absolutely crusted with dried white streaks—my cum, from months of me jerking off into them.
Mia stared. Another pair was tangled with it. Then a third. The drawer was a filthy treasure chest—dozens of Sophia's thongs, bikinis, even silky boy shorts, every single one painted thick with layer after layer of my loads. Some were stiff as cardboard. Some still faintly damp from last week.
Her pussy clamped down around me so hard I saw stars.
"Oh my god…" she whispered, voice trembling with pure lust, not anger. She held up the cum-stained thong like a trophy, dangling it between us while she kept riding, slower now, savoring every filthy detail. "You've been stealing Mom's dirty panties? Jerking your fat cock into them and shooting load after load all over her lace?"
Her hips rolled in nasty little circles. Fresh slick gushed around my shaft, dripping down my balls.
I tried to speak—but she just laughed, low and delighted, and shoved the crusty thong right against my lips.
"Smell it," she ordered softly. "Smell how much you've been fantasizing about Mommy while you fuck your stepsister."
I inhaled. Sophia's pussy scent mixed with my old cum hit me like a drug. Mia's eyes rolled back in bliss.
"So you've been jerking off to Mom's panties?" she growled, slamming down harder, making the bunk squeak dangerously. "Now you get the real thing… both of us."
She rode me like a demon—fast, sloppy, tits bouncing wildly, one hand still clutching Sophia's ruined thong. Her free hand dove back into the drawer, pulling out another pair and pressing the stiff lace straight against her clit while she bounced.
"I'm gonna cum," she panted, voice cracking. "Gonna cum all over your cock thinking about Mommy's panties… and how she's gonna take this dick next."
Her walls fluttered. Squeezed. Milked.
I exploded—second creampie of the night—pumping fresh, thick ropes deep into her already overflowing pussy. Mia slammed down one final time and came with me, thighs shaking violently, biting my shoulder to muffle her moan.
When she finally slid off, another huge glob of my cum poured out of her and splattered onto the sheets. She looked down at the mess, then at the drawer full of Sophia's ruined panties, and grinned like the devil herself.
"Tomorrow night," she whispered, dangling one of the sticky thongs in front of my face, "we're gonna fill a fresh pair together… and leave it right where Mommy will find it."
She climbed down the ladder, still leaking, and curled up on the bottom bunk like nothing had happened.
I lay there staring at the open drawer, heart pounding, cock already twitching again at the thought.
Sophia's panties. Mia's obsession. Four months of sharing this room.
We were never going to survive it.
End of ch 4.