You make sure that she can't resist the opportunity

You were confident in your abilities, beating Samantha in some form of fight shouldn't be impossible providing you can keep a cool head while ensuring Samantha is anything but calm. Part of the long-term plan your parents had set out for you, involved various athletic past times to ensure your body was as well-tempered as your mind. You practised a number of martial arts for the discipline aspect to help you better focus yourself in stressful situations. Being able to defend yourself was just an added bonus.

Samantha was a strong opponent with a considerable amount more experience in competition fighting than yourself. However, in the days leading up to issuing your challenge, you can confirm a sneaking suspicion that you had when learning about Samantha's micro-dosing habits. That she was taking the gene mods to supplement her athletic prowess.

The additional hormones and trace amounts of the genetic tech which give gene mods the power to overwrite the body's makeup, allowing Samantha to shape her body better. Strictly speaking, there wasn't any restriction on this practice, although that's mostly down to a lack of ability to detect it after the fact. The microdose would be absorbed into the body, so short of catching her with her pants down just after dosing while training there wasn't much anyone could do.

On your first day visiting the gym where Samantha likes to train and where her illicit matches were held, you saunter into the gym, paying for a couple weeks membership. The gym itself isn't anything special, with all the standard equipment you'd expect, the bassy pump of some unknowing music to encourage the people working out. You spy Samantha running through a holographic trail on a treadmill, you spend the day getting some exercise and watching Samantha's routine. You're pleased to find that despite slacking in your older fitness routines since being kicked out of college, all the sex you've been having has more than made up for it.

The next few days are the same, you silently watch Samantha from afar, as to not draw much attention to yourself, not wanting to insert yourself into her life just yet. On the fourth day, you manage to overhear a very interesting conversation between Samantha and one of the personal trainers for the gym.

"We got any takers?" Samantha asks while refilling a water bottle and wiping her brow with a towel.

"Nothing yet," The man replies with a smile. "Although after what you did last fight, can't say I'm surprised," He adds with a wry chuckle.

"Hardly my fault, that little skank said she could handle me," Samantha grunts, taking a swig of the water.

"Didn't mean you had to fuck her ass, make her clean you with her mouth, before breeding her in the ring," The man says shaking his head and laughing. "Not that I'm sad you did, but it's going to take a while to find any fresh blood dumb enough to take you on," The man replies with a shrug.

"Void damn it," Samantha groans slamming her hand into the wall beside her. "I need to take the edge off, this last batch has me hornier than the void devil on all sluts night," She adds rubbing her legs together. "Damn thing is starting to appear in my sets," Samantha adds in a lower tone, gesturing down to her tight grey leggings where a prominent outline of a cock can be seen.

"I keep telling you, this batch was the same as the last," The man replies shaking his head.

"Don't bullshit me, Daniel," Samantha snaps, looking around conspiratorially, while you continue to pedal the hover bike you were busying yourself with. "I know this batch was different," She adds in a hushed tone.

"Just the applicators, it's the same strength, you've just been using it too much, I warned you this would happen," Daniel explains. "Ever since you had your plan to breed the girls after the fights, you've been taking more than your body can comfortably absorb," Daniel continues shaking his head. "Probably just as well we don't have anyone for you to fight," he adds.

"I'll be fine, just need to make it through these trials and I can cut back just like we originally planned," Samantha explains with a sigh. "I just need to need someone to blow a load inside and I'll be great," She adds with a sigh.

"Fine, I'll see what I can do, but if your cock doesn't fade away this time, don't come crying to me," Daniel says shaking his head and walking off towards the staff area of the gym. "I told you hundreds of times, the male gene mods were much more stable, but no you had to insist on it being futa," Daniel continued to mutter under his breath as he walked past the hoverbikes.

At this point, you feel like you have everything you'll need to secure your win over Samantha. Not only was she micro-dosing gene mods, but it seems as though she's getting dangerously close to having them add up to a full dose. You consider whether all she might need is a not-so-gentle nudge in the right direction, after all, Samantha clearly enjoys certain perks of the futa lifestyle. If nothing else the dizzying mix of additional hormones in Samantha's body might give you an additional way to fight in the ring. By teasing her and making her so horny she can't think straight.

With some good insight gained, you decide to move on to the next stage of the plan and introduce yourself to Samantha to try and lure her into wanting to fight you. You watch with intrigue as Samantha continues to work out for a little longer the outline of her cock twitching as she moves. Soon enough Samantha finds herself too hot and bothered to focus on her routine and makes a move towards the showers. You give her a minute before getting up and following her.

You spot Samantha at the far end of the locker room, trying to rub her aching cock through her leggings while glancing around to make sure no one could see her. You wait just long enough for Samantha to feel confident enough that she was alone and she pulls down her leggings, her cock springing free. You slowly and silently continue your approach while Samantha begins to stroke her cock, letting out soft groans of pleasure she was muffling by covering her mouth with her other hand.

You can sympathise with Samantha, knowing just how unrelenting your futa urges can be, the dizzying mix of the hormones can overwhelm someone who's lived with them for years. You've got a good handle on your own urges but you've lived with the hormones a lot longer than Samantha has. You watch with a smile as Samantha tries her best to pleasure herself to take the edge off, but you tell from her technique that she was going to struggle.

You silently approach until you're only a row of lockers away and lean casually against them, watching Samantha's hand flail up and down her shaft. You start to undress until you're down to just your sports bra and boyshorts, your own tool stirring in sympathy for Samantha's plight, or more realistically for what you have planned for her.

"Did they not teach you how to do that properly in health classes?" You ask in a teasing tone, a big broad smile on your face.

You watch with some small satisfaction as your sudden words make Samantha jump, her wide eyes focusing on you and you shake your head and laugh while pulling down your boy shorts and revealing your own cock. You watch her mouth open and close a few times, desperately scrambling for words, before you decide she's squirmed enough.

"Hey I'm not judging, I know how a good workout can get more than sweat flowing," You offer, gesturing down to your own erection. You watch Samantha's eyes flick down to your cock, you see her swallow.

"It's not like that," Samantha eventually replies nervously.

"What do you mean?" You reply with a smile before looking Samantha up and down, appreciating her toned athletic physique for a moment. "Oh wait, I think I get it," You add with a smile. "Uncontrollable urges, shitty masturbation technique, nervous around another futa," You begin to list before flashing Samantha a big smile. "You're just a part-time Sister, Aren't you?" You conclude with a broad grin.

"Maybe, I am, is that a problem?" Samantha replies with a hint of aggression in her voice.

"To some perhaps, but not me," You reply in a soft tone, "Personally I'm not sure why you wouldn't keep the cock full time, but I'm sure you have your reasons," You continue taking a few steps closer towards Samantha. "Can I at least offer you some advice?" You say with a sensual tone.

"Sure," Samantha replies hesitantly.

"A little moisture can go a long way," You explain, before licking the palm of your hands and reaching down and stroking Samantha's cock. Samantha recoils back in surprise at your sudden touch but stops herself when she feels how good your hand feels. "Also don't squeeze yourself so tightly, sometimes a lighter touch is better," You offer, as you relax your grip and continue to gently stroke Samantha's cock.

"Fuck that feels good," Samantha groans.

"Good, now go put those lessons to good use," You reply taking your hand away from Samantha's cock.

"Wait, don't stop," Samantha pleads.

"Look I'm happy giving you a helping hand and some pointers, but I'm not going to jerk you off to completion," You reply with a smile.

"Please, your hand feels so much better than mine," Samantha pleads.

"Fine, but you'll have to help me out with something in return," You reply with a smile.

"Sure, anything, just touch me again," Samantha says.

"Alright, but maybe we should hit the showers, before anyone else walks in," You reply with a smile.

A few moments later you're standing behind Samantha in a shower cubicle with your cock sat happily between her perky butt cheeks like a big thick hotdog in a bun. Your hands reach around Samantha's athletic frame, with your hands dancing up and down her stiff pole.

"So I heard a little rumour that there is some illicit fighting going on in this gym," You whisper into Samantha's ears. "Something about the winner getting to fuck the loser," You add in a sensual tone. "You wouldn't happen to know anything about that, would you?" You ask in a teasing tone.

"Yeah, I've participated a few times," Samantha groans. "It's the main reason I'm part-timing as you put it," She adds with a grunt of pleasure.

"Really?" You reply in mock surprise. "Now why would you need a cock to fight?" You add, switching out your grip and teasing the underside of the sensitive head of Samantha's cock. You feel the cock twitching in your hands, letting you know Samantha was getting nice and close, which is why you slow your hands down.

"Not to fight, but to fuck my opponents afterwards," Samantha explains, trying to thrust her hips to **** a faster pace and bring herself over the edge you were keeping her on.

"I suppose that makes sense," You offer, keeping your movements frustratingly slow to tease Samantha. "So is it just women you like to fight, or do you get a kick out of bringing men down?" You ask, knowing already Samantha only fights women.

"Women only," Samantha grunts as you tease her right to the edge once more, her shaft throbbing in your hand before you stop.

"Just women? Don't fancy emasculating a cocky man in the ring, and then emasculating them again with their ring?" You offer in a teasing tone.

"No," Samantha grunts.

"Why not?" You ask in a teasing tone.

"Because I can't knock up a man," Samantha grunts, her cock painfully close to cumming as you run a solitary teasing thumb across the twitching underside of her shaft.

"So you like to breed your opponents?" You reply with a sensual tone. "That's so fucking hot," You add picking up your strokes to bring Samantha right to the edge of orgasm once more. "How do you make sure it sticks?"

"Rules of the competition, the winner can do almost anything with the loser," Samantha replies with a frustrated groan.

"Wow, so what do you do?" You ask

"Find a woman to fight, they feel safer since I'm all woman too," Samantha begins as you continue to tease the information from her, although it's all information you knew already but it is good to hear Samantha confirm it. "I then dose myself up to grow a cock, then make the women take something to make sure any birth control they have is disabled and my new swimmers have a fighting chance," Samantha continues to explain.

"Oooh so fucking naughty," You purr bringing Samantha to the edge of orgasm once again.

"It's so good, the look on their faces when they realise what I'm about to do to them," Samantha groans, "They think I'm like them, just looking for some extra credits, but I love that moment when I can see it in their eyes when they realise I'm going to knock them the fuck up," Samantha pants, her cock throbbing wildly in your hand, until your squeeze it as hard as you can halting the orgasm in its tracks.

"Oh fuck that's wild," You tease. "How many have you knocked up?" You ask

"Fuck, I need to cum, let me cum already," Samantha pleads.

"How many," You repeat.

"I dunno at least 12, of the 50 tried to sue the gym because they got pregnant," Samantha grunts "Pretty sure my numbers are higher than that though" She adds. "Now will you let me fucking cum already" Samantha pleads in an aggressive tone.

"Soon, I just want to know one thing," You say reassuringly.

"Ask," Samantha grunts while wiggling her hips and attempting to thrust to do anything to finally give her that last nudge to cum.

"Would you fight me?" You ask in a teasing tone. "After all, my pussy is just as ripe and fertile as any of those other girls you've fought," You add in a teasing tone.

"Oh fuck," Samantha groans.

"Of course, unlike all the other matches, I'll be fighting knowing what you want to do to me," You explain in a sensual teasing tone. "Better yet, I'll be wanting to do the same thing to you," You add feeling Samantha's cock twitching in your hand.

"Fuck," Samantha pants, turning around suddenly and staring you in the eyes her breathing heavy from your skilful handiwork.

"It'll be a real test of your skills, high stakes, and high rewards," You say in a soft tone, running your hands over Samantha's toned stomach.

"It's real tempting," Samantha says.

"Then let me give you a little more incentive, by leaving you hanging," You offer in a teasing manner, turning and walking out of the shower cubicle.

"Oh you fucking bitch, We're definitely doing this," Samantha growls, wrapping her own hands around her cock, and trying desperately to get herself close to the edge again.

"Let me know when and where," You say teasingly as you continue to walk away, leaving Samantha thoroughly frustrated as she struggles to get herself off