The Breeding Stallion

When my lesbian sister Tedi married her bisexual college girlfriend Winnie, I never imagined they would ask me to be their sperm donor at all, much less in quite the way they proposed. I knew they wanted kids. I also knew Tedi only insisted on exclusivity regarding other women and was perfectly happy for Winnie to have up to one male partner at any given time, as long as she was consulted before anything more serious than kissing happened. I just never anticipated that those two facts about their relationship would lead them to...this. I was flustered but honored when they asked me to donate my sperm, and I had to admit Tedi's reasoning made a weird sort of sense.

"In an ideal world, we could have at least one kid that was biologically both of ours, but this would be like the next best thing," she had said. "Winnie would be dipping into practically the same gene pool as if I'd magically sprouted a working set of male parts. Mom and Dad would be the baby's biological grandparents, and you could basically be like the fun uncle that he or she just happens to call 'Daddy,'...if you want that, anyway. 'Uncle Wally' would be fine, too. It'd be up to you."

Even though Tedi and Winnie would bear the legal and financial responsibilities, the possibility of having a child at only eighteen years of age was not a decision I wanted to make lightly. Ultimately, however, I agreed. I loved my sister and considered my sister-in-law a good friend by then, and I welcomed the chance to help make them even happier than they already were together, as having children clearly would. Plus, I had to admit the idea had an oddly primal appeal to it.

"It's gonna be a bit awkward collecting my sample," I confessed after informing Tedi and Winnie of my decision in the kitchen of the ranch house they lived in. "But it shouldn't be too hard."

"Well, with Winnie's blessing," said Tedi, looking slyly at her wife, "I could share some of her naughtiest private selfies with you if you think a personal touch might help." She rolled her eyes at the nervous surprise on my face. "Please. You really suck at discretion sometimes, or maybe I just know you too well. Either way, don't even try to convince me you don't check my wife out almost every chance you get." She shot me a wry smile, as if daring me to protest.

I blushed, unable to deny it. Winnie was a curvy, raven-haired babe whose intelligent green eyes were made no less cute by the dark-rimmed glasses that often adorned her naturally alluring face, and below the neck, I was often unsure whether her breasts or buttocks were her most enticing feature, though I suppose the answer at any given time likely hinged on whichever happened to be best emphasized by her clothing. In that moment, for instance, her tank top accentuated her considerable cleavage, though her snug gym shorts left little to the imagination below the waist as well. Swallowing, I chuckled and shrugged mostly to ease my own awkwardness. "Fine," I conceded with my best attempt at a cheeky smirk, "but it's not like you're the master of discretion yourself."

I took some satisfaction in seeing Winnie blush too, even as she smirked and raised her eyebrows in apparent amusement. If that expression didn't dispel my brief concern that she might be offended or creeped out, what she said next certainly did. "Dirty thoughts about your sister-in-law?" she teased with a smirk of her own. "I suppose I shouldn't be surprised. After all, it makes sense for siblings to have similar taste. Besides," she shrugged, "I can't say I've never given him a second look either."

"Yeah, 'cause that's a shocker." My sister punctuated her sarcasm with another roll of her eyes, though for me, it actually was something of a shock. While I'd been convinced by a lifetime of compliments that at least my face was easy on the eyes, I suspected that my sex appeal likely tapered off below the neck, where I was rather scrawny and a bit on the short side.

Winnie's casual nod turned rather suddenly into a pensive tilt of the head, and she turned to meet Tedi's gaze. "Tedi..."

"Yeah?" my sister replied, narrowing her eyes in amused curiosity at her lover's thoughtful expression.

"How would you feel if he made his donation...au naturale?"

Despite my blood immediately starting to pool southward at the implication, I laughed at what I felt safer assuming to be a joke, but Tedi narrowed her eyes in recognition that her wife may not have been kidding. "You're serious?"

Winnie seemed to grow even more sure of her proposal as she nodded. "I mean, sure, it's a bit wild, but it seems like a win-win all around. I get his seed in me, and we both get to have some fun in the process!"

"Hmm," Tedi mused, oblivious to my slack jaw and sharp inhalation as she appeared to genuinely entertain the idea. "I don't see why not," she nodded with finality. "It'd probably save money on in vitro, too! I'm not seeing any downsides here, except maybe that he doesn't live with us, which might make it a bit harder to try on a reliable basis." She paused. "I suppose he does visit often enough, so as long as we make sure to take advantage whenever he does, it could still work. Especially since, if the look on his face right now is any indication, it'll probably be pretty easy to get him in the mood, even by usual male standards."

I gave a brief sarcastic laugh at my sister's jab, but Winnie's own giggle reminded me of what exactly seemed to be unfolding here. I blinked and let out a nervous chuckle. "Wait, wait, wait. Are you two suggesting what I think you are?"

"Do you think we're suggesting that you and Winnie just start having sex with each other, preferably on as regular a basis as you can?" said Tedi.

"Oh, wow! You are, aren't you?" I marveled, a nascent grin tugging at my lips.

"I can be your sister-in-law-with-benefits, and you can be my breeding stallion!" Winnie summarized. "I'm game if you are!"

"Well, I mean, of course! It's just...so unexpected, I don't quite know where to go from here!"

Winnie leaned forward a bit, her upper arms pressing her breasts together in what I suspected was a deliberate gesture. "Well, let's just...give in to our urges a bit and...see what happens." My jaw went slack as she ran her hands up my thighs and stroked my quickly stiffening cock with her thumb.

"Jesus!" I hissed at the contact. "Right here? Now?"

"You heard Tedi," she smirked. "You don't live with us, so if you're gonna get me pregnant, we probably shouldn't waste any opportunities. You're here, and we're both clearly in the right mood." Never breaking eye contact, she lowered herself from her chair to her knees and kissed the base of my pants fly. "You're already so hard!" she giggled again.

I let out an undignified groan and was practically panting as I spoke. "Okay, look,...if we're going to do this,...you should probably know I've only done this twice before,...so I'm still a bit of a lightweight, if you know what I mean."

"Then maybe you can use this little arrangement to build up your stamina," Winnie said with a shrug as she trailed a couple more kisses along the length of my member through my jeans. "But at least for now, don't worry too much about that." She met my gaze and, licking her lips, unbuttoned my pants. "Even though there'll be at least a bit of pleasure in it for the both of us, the only ultimate point here is insemination." She unzipped my pants and kissed my shaft again, this time through my boxers. "I'm sure Tedi will be more than happy to step in if you finish too fast for me." She let yet another kiss linger on the tip of my cock, her lips separated from my glans by a single thin layer of fabric. "Hell, she'll probably thank you for warming me up!"

Somehow, mention of my sister in such a sexual context did little if anything to dampen my arousal. With such a gorgeous non-relative now reaching for the hem of my boxer shorts and literally asking me to cum inside her, it was easy to forget that Tedi was even in the same room. I couldn't believe how bold Winnie was, but it was driving me wild, and I had the distinctive feeling that, if I didn't get my dick in the right hole soon, the load I had quickly building up would likely end up going to waste.

As Winnie tugged at my pants and underwear, her doe-shaped eyes met mine once more. "Now, do you have any special requests to really get your motor going..." With a sly grin, she glanced downward at the tip of my now fully erect member peeking out from my clothes and raised her eyebrows. "...even more than it already is?"

I reached for her firm mammaries, their alluring shape and size obvious even under her top. They were ample domes, each with a voluptuous balance of diameter and depth. Plus, her thick nipples seemed even more prominent than usual. "Well, let me just..." I trailed off as I gently squeezed a warm mound in each hand.

She gave a playful gasp. "I'm not surprised you went straight for my breasts," she cooed before once more kissing the tip of my now bare dick.

I managed to play with them only briefly before a soft moan from her finally sent me over the edge. She had hardly wrapped her mouth around my manhood for some deeper oral stimulation before I suddenly rose to my feet, pulling her up with me, and gave her butt an appreciative squeeze before hurriedly spinning her around and sucking on her neck from behind. At this Winnie emitted a pleasantly surprised moan, and raw instinct drove me to engage in some brief gluteal frottage while I hastily unfastened my pants and finally freed the full length of my cock from its fabric prison.

"Oh, okay," she realized in amusement, "I guess we're skipping the usual blowjob."

"Honestly, at this point," I explained, slipping a hand down her panties and caressing the hirsute contour of her mons, "I just want to put my cock in your pussy."

Somehow, my bluntness seemed to turn Winnie on a bit more. I heard her breath hitch in her throat before she spun herself around to face me, cupped my face in her hands, and gave me a searing kiss on the lips. "Then do it, Wally," she said, as she peeled her shorts and panties down in a single motion. "Just put your cock in my pussy."

I only took a brief moment to enjoy my first sight of said genitalia, comprised of two snug labia tucked inward into a tiny slit adorned by a dark bush that seemed to be compensating for her natural shortage of body hair anywhere else. Before I knew it, Winnie was completely bottomless, my own bottoms were around my ankles, and I had planted her naked and very shapely ass on the nearest countertop. I heard her gasp as I slid my very erect dick into her pussy, but her legs tightening around my abdomen and her arms around my neck reassured me it was a good kind of gasp. I let instinct take over once more and began thrusting into her without inhibition.

"Fuck me, Wally!" she said with a gaping smile and a cute giggle at my obvious desperation. "Fill me up with your cum!"

She was clearly experimenting with how best to keep my arousal high, and although I definitely couldn't complain, I ultimately cut her off with another deep kiss while drawing her breasts out from her tank top and caressing the spongy mounds of hot flesh, which elicited a moan from her that I was eager to hear again. She bit her lip and leaned her head back with half-lidded eyes as I accelerated my thrusts, and I could've sworn her vaginal walls were already starting to feel moist as they clutched my swollen member.

I'm not sure how long I actually managed to keep ramming my engorged dick into her tight pussy, her torso visibly bouncing against the counter throughout while I continued kissing her and massaging her supple tits. Whether the time only seemed to fly by because of the intense pleasure or my stamina really did need work, a part of me felt oddly disappointed as I finally felt the hot pressure building to a fever pitch and pooling in my glans.

Winnie arched her back and her already heavy breathing began sounding downright ragged. Her forehead resting against mine, she rotated her eyes upwards to meet my gaze and spoke through parted lips. "Cum in my pussy, Wally. Just let it all go deep inside me!"

If I wasn't already within seconds of reaching climax, that straightforward command and the viscerally primal appeal the idea seemed to hold for me would've done the trick. At this point, I didn't want to cum inside her. I needed to cum inside her. I gripped her waist tighter, and we rested our heads on each other's shoulders for the final few feverish thrusts and hip rolls. With an impassioned groan, I finally exploded with a thick jet of cum, evoking a deep, drawling moan from Winne while my entire body spasmed against her.

"Wooh!" she breathed. "That was..." She trailed off as another spasm rocked my hips and sent another plume of semen into her pussy. I pulled back just enough to look into her emerald eyes, which danced with humor as a grunt signaled a third ejaculation. "Oh, wow!" she chuckled, "You're still...!" Her mirth turned to confusion and then gaping shock as I helplessly sent two more surges of seed into her body, each not quite as voluminous as the first but pretty close. "Holy shit, Wally!" she said in awe after I finally went limp with a sigh. "I'm aiming for one baby at a time, not a whole litter!"

I took in her somewhat dazed and bedraggled appearance. "Did you cum? I can't really tell for sure."

She sighed, clearly having enjoyed our encounter even if not to the point of climax. "Honestly, not quite, but it was still fun, and like I said, that's not really the..."

I guess the next word would've been "point," but it was drowned out by a sudden sharp intake of breath, as somewhat on a whim, I inserted my index and middle fingers between her labia and into her vagina, from which some of my semen was still dripping. As they slid in, my digits first rubbed against what had to be her clitoris, given her reaction.

"Oh, f-f-f-f-fuck!" Winnie stammered, her mouth falling open in ecstatic shock. She slammed her palms on the surrounding countertop a couple of times. Grinning in triumph, I withdrew just a bit only to make another venture, now making sure to press the heel of my thumb against her clit. "Mmm!" she intoned. "Don't stop! Don't you fuckin' stop!" A shudder accompanied the next penetration. "I'm too close now! I need to cum!" She rested her elbows on the counter behind her and gave in to my ministrations, leaning her head and chest back with half-lidded eyes. My fingers now coated with some of my own prior effusion, I took the opportunity to press my mouth to the nape of her exposed neck again, eliciting a moan from her which was probably enough all by itself to put a serious dent in the time it would take me to "recharge," so to speak. All the while, I kept repeatedly ramming my fingers into her pussy, doing my best to titillate her clit as well with each thrust.

It was clearly working, because I don't think it was even quite a minute before Winnie cried out, "Oh, my God! I'm cumming! I'm...aaaarrrrrggghhh!" With a primal grunt of ecstasy, she flung her arms around my neck and shoulders for support as her hips twitched violently against the surface on which she sat. With a final spasm that rocked her entire body, she let her eyes fully open and met my gaze. Letting out a breathy chuckle, she smirked. "Okay, casanova, you got me good!" she admitted playfully. "Just be careful next time, if you blow your load a bit early again but still insist on being a gentleman. We can't have your fingers pushing out too much cum if you're gonna knock me up." She sighed and slid back onto her feet before me. "At least this time, though, I doubt it'll matter, 'cause you came like a fuckin' racehorse!" She shook her head in renewed awe. "I mean,...Jesus, Wally!"

I took a moment to catch my breath before responding. "What can I say? That's just what you do to me!"