Jack and I fucked ourselves senseless all that day, and far into the night. It's a cliche, but I lost count of the number of orgasms.
The news of my pregnancy had worked my son into a frenzy. He was unstoppable. No sooner had he cum than he was hard again. How he replenished the supply, I don't know, but by the end even Jack - with those big balls the size of kiwifruit - was shooting air.
That first time, our first fuck of the morning, I'd told him as he rode me to the finish line. Told him the news he had been dying to hear.
"Cum with me, darling," as the quivering began and the butterflies fluttered. "Shoot more babies into my pregnant belly."
"P... pregnant?"
"You're a father now. I'm carrying your children, Jack." The quivering was out of control, painfully sweet. "You've bred me. I'm a month along and nothing can stop me now. That cunt you're fucking is going to give you two beautiful babies."
At that last word, his jaw tightened, and I saw it: there, under his chin, where only a lover - or a mother - would ever notice. Cut open at 14 by a cleat to the face at second base. I remembering jumping to my feet in the bleachers and screaming as I saw the blood dripping down his shirt. But he insisted on staying on the field, and the wound wasn't cleaned and taped until the game was over, so it hadn't healed over properly.
There it was now, a hard ridge of skin that was a reminder that for 18 years we had had a life before he had come to my bed; that we were mother and son before we became mother and lover; that there had been nappies and birthday parties and Little League games and scabby knees and first days at school and homework and braces and ice cream at the beach, and that the man pounding away between my legs had once been a baby between my legs.
"I did it for Mom," he told his father after the game. "I wanted to show her I'm not a quitter."
I caressed his scar as he approached the end. "Do it for Mom," I managed to gasp before I imploded in on my own orgasm.
His eyes were boring into me as hard and deep as his cock was boring into me. This was heavy fucking. I knew the bruising would last for weeks, inside and out. One wordless roar as he plunged into me, his cock-head hitting something far up inside me.
Then a torrent of words as he unleashed his seed. "Our babies, Mom! It's all I've ever wanted. You and me and our babies, forever."
And that's how it went all day. One long fuck, punctuated by half-hour breaks while we recovered, then I would whisper to him: "Our babies" and he instantly stiffened.
When finally I drifted back to earth from my eighth - or was it ninth? -- climax and Jack's limp-at-last dick slid out of my stretched, soaking hole that evening, we fell into the deepest unbroken sleep. We were still dead to the world in the morning when I heard the front door slam. Jack reached sleepily for his phone.
He texted his sister.
Upstairs. Mom's bed.
Cassie was at the door in seconds. "My God, this room reeks of sex. You two must have been fucking all day yesterday and half the night."
"That's exactly what we've been doing. It was my last day alone getting railed non-stop by my son. From today we start sharing. This is your big moment - just you and Jack. It's opening night."
Opening you up night.
Cassie sat on the bed next to me and held my hand. "I can't tell you how much I've wanted this," she sighed, giving me a melting, doe-eyed look that made my pussy surge. "But are you okay with it, Mom? This whole... thing?"
"Darling, it's going to be amazing. Me, Jack, you and Dad - one big happy fucking family."
"That's all I want, Mom." Her hand went to the back of my neck. She drew me in and our lips met. It was a shockingly erotic act, for someone who all her life had been simply my daughter. My lips parted slightly and I was falling into my first kiss with another woman. God, it tasted good. Her tongue slipped into my mouth, in a way that was indefinably feminine, but utterly authoritative. Soft yet strong, she was in complete control.
My head was spinning, my clit was pulsing as she released me and sat back. I realized with dismay that the sheets had slipped and my breasts were on full display, my nipples pink and swollen with a shameful desire that no mother should have. Blushing furiously, I covered myself and stammered an apology, but she put a gentle finger to my lips and gave me an enigmatic smile.
Everything had changed. We both knew it. In those few seconds, she had taken command, and we could never be simply mother and daughter again.
One big happy fucking family.
I said the words confidently. But in the back of my mind a doubt had begun to gnaw at me.
Will I regret this? Was that mysterious smile actually a smirk of triumph on Cassie's face? Has she just taken - no, have I just given away - the most important thing in my life? It all seemed so exciting yesterday, but now that it's about to happen...
I couldn't dwell on it for long. My children were eager to start. I showered and changed the sheets. I wanted things to be clean and fresh for when Jack mated with his sister for the first time. But in truth, I realized my children just wanted to fuck each other. In bed, on the carpet, in a patch of dirt if they had to.
That first time was a cosmic collision of bodies.
Two beautiful 19-year-old twins dedicating themselves to each other's pleasure. Cassie, her perfect body, snow white, touched with pink at the nipples and between the legs; pregnant, though not yet showing. Jack stiff and urgent, his muscled body eager to get to work.
And there's me. A buxom mother helping her children mate, in defiance of every law of man and nature. Kissing and caressing, I ensure that she is wet enough to take her brother's abnormal girth and length.
When the time comes, when her sighs and her body movements and her flowing juices tell me that she is ready, I guide Jack's cock-head to Cassie's cunt. I am deep-tonguing her as he begins to penetrate her, and I am rewarded with her gasp at his size.
My fingers explore the place where their genitals join, feeling him inch his way remorselessly into her tightness. She cries out - "It's too big, Mom! It won't fit! Make him stop!" - but there's not a force on earth that could make him stop now, at the entrance of his pregnant sister's birth canal. After a few abrasive thrusts it gets easier and he begins to feed more of his thickness into her and her cries fade and he starts to ride her.
My hand is at her cunt-hole, feeling his shaft move in and out, a smooth piston of flesh, as Cassie gets a professional fucking from an expert. I revel in the rhythmic slap of his balls on her ass, the sound of a hard tool going to work on a tight pussy, a raging stallion riding his mare.
It should have been a fantastic experience. And it
was
. Sort of...
I caressed and I kissed and I cajoled, but in the back of my mind, I had to admit that I wasn't actually
needed
here.
It was a privilege to be present at my children's first incestuous coupling, but something nagged at me: I didn't feel involved. My presence in bed with them was just a sign that I assented to this new relationship; that I couldn't back out, couldn't go back to just Jack and me. They had explained the contract, I had signed it. Everything had changed, forever.
When they came, loud and uninhibited, beautiful teenage bodies crashing against each other, Cassie's cries of pain having given way long ago to sobs of pleasure, I don't think they were even aware I was in the room.