Forever Hung (Part 20) [sci-fi] [slow burn] [all characters over 21] [MFF] [voyeur]

I closed my book and carried it with me into the hallway. I walked toward the east wing. I listened carefully outside a door, and hearing no one inside, I turned the knob and crept into the professor’s study.
The door to his bedroom was closed. Glancing about, my eyes fell on the statue of Clara, the body I now knew.
I drew the blinds as tightly as possible, then sat in the professor’s desk chair and wheeled myself into a discreet corner behind a ficus. Too dark to see, I illuminated my book with my cellphone light. And I sat, and I read, and I waited.
I read close to fifty pages. Essays about the electrification of the Chicago River. About century-old litter left on the peak of Mount Everest. About an abandoned hotel on the outskirts of the Uyuni Salt Flat. And I began to suspect my hunch was wrong.
But at last the hallway door creaked open. I killed my light, closed the book. I saw a figure tiptoe into the study. Two figures. The door closed behind them and there was only darkness. Silence, the creaking of floorboards, then a knock.
“Professor?” Madison said softly.
A befuddled “yes?” through the door.
One half of the door slid open, as if by itself, and through it I could see the professor standing in a smoking jacket and pajamas by a wash basin with a toothbrush in his mouth. I could see his bed, the lit fireplace, and thanks to a standing mirror on the far wall I could see his window, his seaside watercolor, and even the doorway through which I sat. Indeed, I could make out the entire bedroom.
So I saw from two angles as Madison appeared in the doorway. Her underwear was simple, but effective—a pair of cotton hipsters and matching balconette, both the pastel orange of a summer cantaloupe. Her hair was pinned up and delicately braided around the back, a few strands hanging purposely loose in front, and she wore a pair of pure white socks pulled up over her knees. Madison was, of course, a decade younger than the professor’s wife, and the outfit seemed specifically chosen to emphasize her youth.
She slipped one leg into the bedroom, caressing her thigh as she straddled the doorframe.
“Madison,” the professor said wearily.
The door’s other half slid open, also as if by magic, and her double emerged into the light. She wore a honeydew-colored version of the same outfit, but her hair was cut to shoulder length and hung, parted to one side, in loose ringlets. I expected her to straddle the opposite doorframe, but she instead pressed herself against Madison’s backside, looking at the professor as she gently kissed the back of Madison’s neck.
I had no way of knowing what effect this had on the professor, but I certainly felt the effect it had on me.
But his first thought was scientific. “You built a transistor?” The professor asked.
“All by myself,” Madison said. The double looked down. She made some slight adjustments to Madison’s bra straps, straightened her panties.
“You’re so good at moving independently, aren’t you professor?” she said. “I’m still struggling. It’s easy to do the same action with both bodies.” Madison turned to face her double. They wrapped their arms around each other. They kissed, tilting their heads one way, then the other, offering quick glimpses of their swirling tongues.
“But if I try to do two different things…”Madison continued. Her double walked over to the professor’s bed and laid back flat, sliding her hands inside her honeydew panties, the fabric rising and falling in time with the fingers beneath. From my seat I stared straight down her spread legs; in the mirror I saw her resting cleavage. All this as Madison sauntered toward the professor. She pressed herself against his hesitant body. She slipped a cantaloupe strap from her shoulder. She circled a toe, the soft cotton of the sock, across the professor’s bare foot.
“If I try to do different things,” Madison cupped her hand against the professor’s groin, “it gets harder.”
I saw him swallow.
“Can you help me practice?”
“Miss Lounds, please,” he said. “I’m with my wife.”
“That’s just what I mean! Multi-tasking.” She leaned in. She tilted his head to watch her double as she kissed the side of his neck. “Are you fucking her right now?”
“That’s not…”
“Is she going down on you?” She took him by the hands and walked backwards toward the bed. “Are you going to cum in her mouth if we go down on you?”
Madison sat the professor on the edge of the bed. She climbed behind him on her knees, removing his jacket, as her double straddled his lap. Her cleavage hovered beneath his chin. She leaned forward, but instead of kissing the professor, she kissed Madison over his shoulder, grinding gently against him as they moaned into each other’s mouths.
“I can’t…”
Madison pulled him back down onto the bed and threw her leg over his face. She unbuttoned his shirt as she kissed her double.
“This is easy,” she said, opening his shirt. “Both bodies kissing. Both of *my* bodies grinding different parts of *your* body. Both bodies unhooking the other’s bra.” They let each fall to the bed. From where I sat, their perfect triangle, I saw the girls’ nipples grow hard as they brushed against their mirror pair.
“But this…” Madison’s double reached down and tugged his pants below his waist. He was only semi-erect, a fact I attribute, even at his age, to an incredible resistance, a miraculous mental devotion to his wife. The double stroked him with both hands, breaking lips with Madison only long enough to let an orb of their shared spit drip onto his growing cock. When, despite his best efforts, he inevitably rose, Madison’s double held her panties to one side and eased herself down, the tight cunt I knew so well.
“This is harder,” Madison said. She leaned back on her arms, sliding her pelvis back and forth across the professor’s mouth as her double began riding him up and down.
From here the professor began to surrender to his good fortune. His hands started to explore their bodies. Madison’s abdomen, her double’s ass. Madison’s breasts, her double’s thigh. He slipped a finger inside each of their mouths. He arched his neck and rolled his pelvis. Then he rolled onto his side, both girls giggling as they fell against the mattress. He tugged at the cantaloupe panties, buried his face against the honeydew, they soon became a tangle of bodies punctuated only by four tall, white socks, and it was clear they wouldn’t be done before dark.
At which point I realized my own precarious situation. With the sliding doors open, I was trapped. If I tried to leave the darkened safety of my corner, I’d step into the light cast by the bedroom. Worse still: if ,when they finished at last, they reclined on the bed to catch their breath, they’d all be facing the open doorway, where any movement on my part, no matter how slight, might be noticed in the placid, post-coital lull.
I waited for an opportunity to sneak away, but there was rarely a moment when at least one of them wasn’t facing the doorway. Madison’s double, sitting on the headboard, the professor’s head between her legs. The professor, thrusting against one of the girls—I’ve no idea which—as they made out, one atop the other. Madison, her head dangling over the bed, squeezing her breasts as she went down on herself.
At last, the girls laid the professor on his back, his feet toward the doorway. They shuffled toward him on their knees across the mattress, their backs to me. Madison’s double took his cock in her hand, sliding it against her palm.
“This is what I really wanted to practice,” Madison said.
She leaned down and took him into her mouth, her lovely braid bobbing up and down. Then she sat up, held his cock upright, and her double bent over. Her blonde curls draped and swayed.
They stopped taking turns. Madison leaned over and her two mouths shared him in ways I could only imagine, for all I could see was the occasional crest of a head over the shapely ridge of their fair, abutting bottoms.
I emerged from my corner, hastened through the firelight beam, and returned to my room.

Source: reddit.com/r/eroticliterature/comments/11tyaz7/forever_hung_part_20_scifi_slow_burn_all