Bethany Michaels loved this position -- astride her supine stepfather, mounted on his deeply-imbedded prick, joined. In this pose, she could roll her hips back and forth, dragging her sensitive clitoris across his trimmed pubic hair and driving herself into his solid pubic bone, which put her in complete control over the pace of her pleasure. This motion also impelled the adult penis within her, for as each forward slide of her hips provided impulse at its base, basic trigonometry ensured the movement was magnified along its rigid length, so that even subtle pelvic rolls resulted in his hard glans slamming into her forward vaginal wall and fleshy g-spot with significant leverage. And, when she would slide back, the moment-arm worked in reverse, relieving her g-spot while scraping his cocktip deliciously across the firm bud of her junior-high cervix.

Bethany understood these physical dynamics experientially, not mathematically, for geometry class, let alone trigonometry and physics, still lay well in the eight-grade honor-roller’s future. Nonetheless, she was already Dean’s List material when it came to her expertise in enjoying her stepfather’s hefty cock.

With slow, leisurely, undulations Bethany was, in this position, thus able to deeply stir her inner being. She could enjoy this pace for quite some time, but sooner or later her climax would approach, and then she would appreciate her experienced lover taking over, grasping a hip in each strong hand, and energetically driving her forward and backward as she quaked through her orgasm, the cock within her battering at her g-spot while her clit ground through its cum. Yes, she enjoyed setting her own pace during long luxurious screws, but in the end, when it came time for another pinnacle, yielding to literal manhandling was sublime.

After each orgasm, she would collapse on him, his chest hair just perfectly rough against her small, bare breasts and sensitive nipples. She would then catch her breath and feel her taxed vaginal sleeve fluttering around his thick cock, her elastic organ attempting to settle down and recuperate. Soon, he'd begin a gentle thrusting, providing an in-and-out motion missing from the previous action. Given plenty of time, such as they enjoyed today, this would eventually recharge the fourteen-year-old's libido to the point that she would push herself erect, feel the heavy pole shift within her, and begin climbing her personal mountain once more, forward and back, grind, press and batter, all over again.

Don could support her in this way indefinitely, and often they would spend an hour or more so joined, teasing out four or five girlgasms, before tension, need, or a limited window of opportunity would require that Don empty his balls and end the round. Don never came in this position -- that would be a waste, she knew, from both of their perspectives. If he had semen to plant, and he always seemed to have more ready for her, she wanted it pounded into her, hard, either on her back with her ankles over his shoulders, or, like an animal in estrus, from behind as she mewled in heat. Her final destination, her ultimate goal in these sessions, was always a good solid fucking, but this in no way diminished the delights of the prolonged cowgirl ride that brought her to its verge.

"Daddy, can we do this all day?"

"Sure, Bets. Mom's not back for hours. But I want to give it to you a few times by then, so we'll have to take some breaks, you know; I have to cool off and reload, after every time I come."

"Mmm, I like that, Daddy." For a fourteen-year old girl to call the man who married her mother a mere four years previously "Daddy" was unusual and, if done publicly, would attract unwanted attention to their illicit relationship. Happily, there was little danger of this. Dr. Cohen's biofeedback conditioning had easily reinforced her habit of using his first name, Don, whenever they weren't alone, in fact whenever they weren't either engaged in physical or verbal sex-play, which was almost saying the same thing. By the same process, Bethany now had to really concentrate if she meant to address him as anything other than "Daddy" while his cock was in any way in evidence. This lexical conditioning was equally pleasing to both the forty-five-year old man and the fourteen-year old girl who worshipped him.

His hands reached up to play with her tits as she rolled her hips slowly back and forth. She knew that at any moment, this gentle stroking could turn into a hard pinch or twist. Her little titlets were his to do with as he pleased, of course. His actual acts of nipple punishment, when they occurred, stimulated the girl; her awareness of, and submission to, his complete privileges in this regard aroused her even now, despite his current restraint.

"Tell me about your date last night, Bets."

"Daddy, I knew you'd bring that up! It was good. She was so cute about it. A complete civilian, no biofeedback or anything, but so easy to lead. I suppose having an older girl, an eighth grader, sleep over, was kind of a big deal for her."

"This is that Tiffany, the one from church?"

"Yeah, you know, the Asian girl, the one you say has a sweet gap. Tastes good, too."

"Wasn't hard, huh?"

"Never is, thanks to Dr. Cohen and Track C. It's like I know just what to do and when to do it to bring it out of girls."

"So you liked her pussy, huh?" This conversation had Bethany grinding more energetically now.

"Mmm, yeah. Pouty, and not much hair yet. And she wasn't uptight or anything; came easily."

"Nice, so you had her return the favor?"

"Of course, Daddy. I made her eat me practically all night. She got pretty good at it." She drove hard into her stepfather's pelvic bone, addressing a nagging "itch" and propelling his hard cockhead deliciously against her g-spot. She couldn't help but grunt with pleasure. She felt a smirk come over her face.

"What's funny?"

"She couldn't understand why I wanted to come home first thing when we woke up this morning. Couldn’t tell her I needed my Daddy’s dick. She was worried she hadn't done well enough!" Another smirk.

"Poor thing!"

"Yeah, it was cute. I told her she did fine, and that she'd have plenty of opportunity to learn to do even better. I liked fucking her."

"Good girl, Bethany. Yeah, she's adorable, a real yummy morsel. I'm going to want to fuck her, by the way."

"Really, Daddy? C'mon!" Emotionally, she actually was a little irritated, but her biofeedback conditioning made her pussy pulse at the suggestion nonetheless. When this scheme came to fruition, it would be the seventh time one of her pussy conquests had been lured into her home for an overnight, only to get "caught" en flagrante eating Bethany's pussy by a peculiarly vigilant stepfather.

"You know you're my only Special One, Bethany. But we both love to sample fresh pussy, now don't we?"

The girl made a subdued "mmm" sound and extended the range of her back-and forth motion for several cycles as she enjoyed the thought of her second-favorite pastime. Then she decided to be a bit naughty. "How come I don't ever get any fresh cock, Daddy?" Bethany had the ability to arch one of her eyebrows -- her left one -- at will, and she did so just now, looking down into Don's relaxed face. That face barely registered a change, barely betrayed the man's amusement, when the girl suddenly felt a searing sting in her right breast, as the powerful hand upon it twisted the engorged nipple a quarter turn counterclockwise. "Owwww!"

"I know you're just kidding, baby, but I also know you enjoy your punishment." Momentarily motionless, the girl could feel the heavy rod within her pelvis shift and lurch, bearing witness to the fact that her stepfather also very much "enjoyed her punishment." But of course, Don had been completely correct about her own pleasure in it, as well.

"Oh, don't get me wrong -- I was sorely tempted to have Dr. Cohen condition you through protocol D, so I could enter you in the Daughter Share Program and 'borrow' other girls whenever I pleased. Then you would have gotten plenty of strange cock -- I'm sure you'd be very popular with all of the other sponsors, not to mention that horny bastard Cohen."

"Why didn't you, Daddy?" Bethany knew the response very well, but neither she nor her vagina ever tired of hearing it.

"Because in the end, I just couldn't share you. I want to keep you all to myself." The girl felt warmth throughout her being, especially but not exclusively within her mated loins. It made her feel special to be saved to serve one and only one man, a natural female sentiment, although in this case a devotion which biofeedback conditioning caused to imprint more upon that man's cock than is perhaps normal in girl-to-man pair-bonding. Bethany was fully aware that what she felt -- and especially its intensity and sexual focus -- had been germinated and then enhanced through her therapy sessions. Dr. Cohen had made it quite clear that it was perfectly fine -- helpful, in fact -- that she understand everything about how the process worked, that it wasn't some kind of brainwashing or mesmerism. He had stressed that the more she understood the process, the more she would accept it, and that this would prevent her from ever feeling regret. She felt no regret now.

"Daddy, thank you for keeping me to yourself. And thank-you for letting me have fun with girls, too. Even if I dohave to share some of them with you. And share this beautiful cock with them. But I'm your favorite, always, right?"

"Of course, Little One. In fact, I can prove it. Now, do you remember why I had Dr. Cohen put you through the Track E protocol?"

"Sure, the breeding protocol. You said you want to knock me up -- put your baby in me. I want that, too."

"Babies, Bets. I plan to breed you many times. Do you like that idea?"

"Ungh! You know I do. Did you feel that just then, my pussy reacting?"

"Mmm-huh. Those Kegels really pay off -- make your tight little Daddy-hole grip even tighter."

"But Daddy, I didn't need Track E to want that -- I already wanted it, like more than anything. I've told you I sometimes masturbated to the idea even in the 'bad ole days', when I was lying to myself about not loving your cock."

"I know sweetheart, and if you hadn't really wanted it deep-down, the biofeedback wouldn't have changed any of that, as you know. But remember, the main purposes of Track E are to enhance your pleasure in being bred, and of course to condition out vulnerabilities."

"I'd never have slipped anyway, Daddy -- I'd be careful so you'd give me more!"

"I know you believe that, honey, but Dr. Cohen and his colleagues are scientists. For what, fifteen years or so now, they've been conditioning girls with biofeedback, ensuring they never slip up and expose the true paternity of their children, not even in labor, not ever saying something like 'give your daddy a hug' to their offspring, never slipping up and contradicting the cover story."

"But Daddy, you willbe their Daddy, raising them as their ‘step-grandfather’, I suppose, and I really like that."

"Me too, Bets. Let me ask you this…you’ve been taking your basal temperature every morning, recording it?"

"Yes Daddy, that’s part of Track E. So when you’re ready, we can know exactly what day I’m ovulating."

"So where are you in the cycle, today?"

"Just before my temp is going to spike, so yeah, today would be a good day, if I weren’t on the shot."

"And your pussy syrup, still egg-white, examined that myself."

She squeezed down on his cock, recalling the sweet kisses her step-daddy had applied to her little puss during her ‘exam’ this morning, even while her mother was still banging around the house getting ready to leave for most of the day. She loved daddy licking down there, even though her schoolmate conquests, once trained, were all technically better at it.

"Yeah, so all the signs. You know I’m a good student, and good at science, so once you say okay, we’ll know exactly when to do it. A day like today. God! I want your baby so bad! You won’t make me wait too long, will you Daddy?"

"I don’t know, not sure if I’m in any hurry for these cute little nubbins to get all big and swollen, Bets." A gentle twist of both nipples, together, send a jolt up and down the youngster’s spine.

"Daddy! You sure liked Jenna’s tits, as I recall, and they were bigger than mine, for sure."

"Ah, yes. Well, I’m not sure I want this tight pussy to get all stretched out."

"Daddy, stop teasing! You know Dr. Cohen says that at my age, and with the right exercises, I can get it tight for you again."

"You’re really hot for it, ain’t ya Bets?"

"Well, yeah! I want it naturally, but in Track E almost all my orgasms come with suggestions of pregnancy in the subliminal thingy, so yeah, nothing makes me hotter right now."

"Good girl. So guess what? You know you turn fifteen next month?"

"Yeah?"

"According to Dr. Cohen, in this state, were you to present at the pre-natal clinic he and his colleagues covertly own as an impregnated fifteen-year old, they would not be required to make certain child-welfare reports and inquiries that they would were you only fourteen. Of course, being as they secretly run the clinic, paternity tests trying to tie a girl's child to her biofeedback sponsor would be 'corrected,' but still, it's much better that there never even be any additional attention at all. And in this state, fifteen is the dividing line."

"Really? You mean...you can...are you going to put a baby in me after I turn fifteen?" Bethany felt a flash of heat in her pelvis, a sure harbinger of orgasm. Don had always talked about "someday" -- she'd given up hope that it might happen so soon.

"No, baby. That's not quite right."

Deflation.

"You know the contraceptive shot Dr. Cohen gives you, every three months? He just gave you one, like a month ago."

"Oh, yeah, well, like it will last for like two more months, then you can do it, right? And I'll be fifteen by then, so no big investigation. So please...pleeeeease, can you knock me up in two months?" Hope inflation.

"I don't think that will be possible."

Worse deflation.

"Why not?"

"Well, because Dr. Cohen clarified something for me a few weeks back. It's not your age at conception. It's your age when you show up at the clinic, as long as it is still first trimester."

"So...?" confusion, her pelvis now at a complete standstill, although her well-trained vagina couldn't help but continue to reflexively and rhythmically squeeze on her stepfather's adult shaft.

"Well, with that knowledge, I'm afraid I had Dr. Cohen help me play a little trick on you. That last shot was saline."

"What’s that mean, Daddy?"

"Saltwater. Not contraceptive. I won’t be able to knock you up in two months because I’m fucking you pregnant today."

Inflation to bursting! Maybe it was the Track E conditioning, but on hearing this news Bethany found herself climaxing without even moving, and it was the star-spangled, electric kind of cum that went on and on, her stepfather’s handsome face swimming hazily before her eyes, right up until the moment she fainted in euphoria.

-o0o-

"Okay, Bets, let’s plant the first of today’s many spermloads in you. Doc says we gotta do it this way first."

"I know, Daddy, on my back, pelvis tilted up, and looking into your face as you truly breed me. Final imprinting, he says. Plus the gravity helps it ‘set’."

"I get it, baby, and I want to be looking into your face the first time I make our baby in you, too. It all works out. But we got lots of time today, so I promise I’ll give you a dogbone, too."

"Daddy, you say the sweetest things!"

Bethany now found her stepfather’s bawdy sense of humor very amusing, so she was smiling as she rolled back for him, and allowed him to lift her ankles up over his shoulders. Her pussy was humming, as if she hadn’t already enjoyed a half dozen orgasms riding the man like a cowgirl.

"You ready, darlin’?"

"God Daddy, just fuck me already!"

She gasped as he sank into her, more deeply in this position than cowgirl could ever afford. But notwithstanding this more profound penetration, considering that the middle-schooler had just spent the last hour cavorting upon this same imbedded prick, it was surprising to her how special this particular entry felt. Like she was being taken for the first time.

Of course, she realized that this entry wasspecial: she knew that her stud’s mating organ would not be leaving her own today until it had completed its evolutionary function.

"You got plenty for me, Daddy?"

"You know it, Bets," her stepfather grunted as he began to seriously slice in and out of her elevated snatch. "Why do you think…I was out of town on business the last three days?"

"Huh-ghnuh?" Daddy was pounding her pretty hard at this point.

"Yep. Saving up my sperm…knew if I didn’t leave town, your slutty little body would coax it out of me too soon."

"You did that? For me? Oh Daddy, come in me, please!"

And he did, and not for the last time that day by any means. But this would be the one Bethany would remember best, for many years to come. As she felt his flood filling her center, she came, and fainted, once more.