A Prom(ise) Fulfilled

"No fucking way," I said in utter shock.

"PLEASE. I'm begging you," Brad said. He clasped his hands together imploringly. "I wouldn't ask unless I had no other choice."

"You do have another choice. Don't go to prom," I said. "I didn't go my senior year, what's the big deal?"

"You don't understand, this is my last chance."

"Wait, what?" My eyes narrowed in disbelief. My new stepbrother was so much of a jock it was almost comical—6'4 with a strapping physique and a mind singularly focused on sports and sports-related things—he had been held back a year and was actually older than me even though he was still in high school. I had taken it as a given that he had been to prom his junior year with a cute cheerleader or something, since even I had been to prom, despite being an unknown wallflower at my high school. An equally desperate girl had agreed to go with me last-minute and we both had a miserable time. Because of that, I had skipped out on my senior year and spent the night playing video games instead.

"Last year there was no prom because of COVID."

"Oh right." Duh. "Okay, so find some random girl to go with. You're not gonna tell me you have trouble with the ladies now, are you?"

"Dude, all the girls worth going with already have dates. I was supposed to go with Mandy but she got strep throat."

I rolled my eyes. "Okay, so lower your standards then Mr. Star Athlete."

"Look, nobody at my school knows you, right? We can go for a few hours and leave early. We don't have to dance or anything. Nobody will recognize you, especially because..." He paused. "...you looked pretty convincing as a girl."

I grimaced. The previous year I had lost a bet to my new college dorm-mates and been forced to dress up as a French maid on Halloween. A friend had lent me her costume, wig, and had done my makeup, and everyone had been shocked when I turned out to be decently passable, and maybe even cute in the right lighting.

What nobody knew was that I had been secretly crossdressing for as long as I could remember, and I had thought that I could've looked even better had I used my own wig and done my own makeup. It had been terrifying but exhilarating to be dressed up in public, safe in my group of friends, and occasionally treated like a real girl by complete strangers. We all laughed it off at the end of the night, but afterwards, I had seriously considered revealing that side of me to my friends, but always ended up chickening out.

"Setting aside how insane and fucked up this 'plan' of yours is, why would I do this? Why the fuck would I attend prom as the date of a stepbrother I barely know? AS A GIRL?" I was getting kind of flustered and my voice was rising in pitch, but my point was valid. I didn't owe Brad anything. His dad and my mom had remarried after I had graduated and went off to college. We were Facebook friends, which is probably how he knew about my Halloween escapade, but we barely knew each other. I was on a trimester system so I had come home while he was still wrapping up his school year, but this was the first time we had even shared a roof.

"Please, do this for me and I'll do anything you want! Please!"

"I don't need anything from you, dude."

"Fuck. Uh..." His brows furrowed and I could almost hear the few cogs in his head turning with great difficulty. "What if I said I could get you a PS5?"

I paused. PlayStation 5's had been out of stock for a while, and I had been dying to get my hands on one. "What?"

Brad's eyes lit up, sensing an opening. "I have a friend who works at GameStop, he can definitely reserve one for you."

I rubbed my chin thoughtfully. Could I actually do this? I had to admit to myself that I had occasionally fantasized about attending prom in a sexy prom dress and sky-high heels, as the entire experience seemed so exclusively, deliciously feminine. Now this unbelievable opportunity had presented itself to me, and I could get a PS5 in the bargain. And...for free?

"Hm...for me? You mean for you, since you're buying it for me, right?"

"Ugh..." Brad sighed. "Right, anything for you, princess."

"Fucking gross, dude."

"So we have a deal, right?" my stepbrother said, his voice giddy with excitement.

"I don't understand why you're so dead set on going to prom. To be honest, it was super whatever."

"...but?" Brad said hopefully.

"...but fine." I sighed. "We have a deal."

* * * * * * * * * *

"What are you doing in there? We're going to be late!" Brad yelled from outside my room. Our parents had put off their honeymoon until the end of the school year, and were in Paris until the end of the month, so we had the entire house to ourselves. Thankfully this meant we wouldn't have to explain Brad's harebrained scheme to them, or why their other son was now in a strapless, ruched, crimson red minidress and hurriedly applying the finishing touches to his dramatic "night-out" makeup.

I had opted for an all-red theme: dark red eyeshadow and bold red lips to match my dress and strappy, open-toed four-inch stilettos that showed off my ruby red toenails. I carefully applied another layer of mascara to my fake lashes, taking care not to smudge the razor-sharp wing of black eyeliner. I took a step back to admire my handiwork in the mirror.

Four carefully placed adhesive bras created the illusion of deep cleavage, and adhesive silicon hip pads helped balance out my figure to create a sensual hourglass. My dramatic makeup seemed almost indecent on my pale, waifish features that had never garnered me any favors with the girls. My lace-front ash blonde wig had been carefully blended and even more carefully styled into a side-part with loose waves.

With a full ensemble of shapewear and my developed familiarity with how to apply my makeup to bring out my best features, I looked way better than I did on Halloween.

I winked and blew a kiss into the mirror. Hell, I'd take me to prom.

Prom.

Abruptly, the sheer insanity of what I was about to do hit me like a tidal wave. Shaking, I sat back down as I realized that this time, I was trying to pass as a girl for real and not as a gag. I just knew they'd see right through me, and I'd be publicly humiliated as Brad joined in on the laughter. In fact, this was probably just an elaborate prank by him. There was no way he wanted to go to prom so badly that he'd go with his own stepbrother. What the fuck had I been thinking? I can't do this, I'd never pass. I felt tears welling up in my eyes, threatening to ruin my hours of hard work.

"Hey, I'm coming in!"

"No, wait—" I said, choking back a sob.

Brad barged into my room, looking sharp in his tailored gray suit, corsage in hand. "Dude, we're gonna be la—"

His jaw dropped open.

"Holy. Shit."

I cringed, bracing for the ridicule I knew was coming.

"You look..." Brad ran a hand through his hair in disbelief. "...hot as hell."

"Stop it," I muttered, looking down. "I know I look ridiculous."

"No, I swear. Even I can barely recognize you. You look better than any girl I wanted to take to prom anyway!"

I felt a blush creeping up my cheeks from Brad's relentless flattery. "Really?"

"Yeah," he said giddily. "This is gonna be fun!"

I couldn't look him in the eyes when I said, "Brad, I don't know if I can do this."

"Huh?"

Overcome by emotion, I felt a confession spilling from my red lips. "I...I don't know how to say this but...this isn't just a joke or prank to me. I've never told anyone this but...I dress up like a girl when I'm alone. Like a lot. And other than that time at Halloween I've never been dressed up in public. I don't want to embarrass myself...or you."

My stepbrother's brow furrowed. I thought the complexities of gender identity were probably confusing him but he shocked me when he said, "Alright, I understand."

"Huh?" I asked, unconsciously echoing him.

"If you don't feel comfortable going, we don't have to go."

"Are you sure? I know this means a lot to you."

"It's fine. It was worth the cost of a PS5 but it's not worth causing you grief over it."

"That's...very sweet of you." I sniffled. "Thank you."

"Don't mention it. But for the record, you wouldn't have embarrassed either of us. I stand by my statement that you would give any girl at the prom a run for their money."

I blushed again. God, I was such a sucker for sweet talk. "You know, you're the best stepbrother anyone could ask for."

Brad made a strange expression, and it took me a moment to realize that I had unconsciously repeated the cheesy line that was uttered in half the fake stepsibling porn on the internet. It was a popular genre and I had watched my fair share of them, and the words must have etched themselves into my subconscious.

And Brad's, apparently.

Sitting down as I was, Brad's waist was eye-level with me, which I told myself was the only reason I noticed a bulge slowly forming in his fitted suit pants.

Did I do that? I was shocked, and if I were being honest with myself, somewhat flattered that a few simple words had the power to garner such a reaction from my stepbrother.

My pulse quickened inexplicably. I now had an inkling of how beautiful, desirable women felt: I had this powerful male specimen wrapped around my little finger and could subject him to my whims. With this newfound empowerment, I suddenly wondered how far I could take it.

"You know, you look kinda nice in your suit...stepbro."

Brad visibly gulped, and looked around nervously. "Uh, thanks. Why are you, um, calling me that?"

I deliberately squeezed my chest together with my arms as I stood up, so he that got a full view of my faux cleavage. Slowly, I made my way to my stepbrother in my stilettos, delicately crossing my legs with each step. He lowered his hands in front of his crotch to use the red corsage to hide what was undoubtedly a growing boner. One caused by me. I had never thought about men sexually, but his obvious desire was stirring something deep within me.

As I drew close to Brad, I was overwhelmed by the fresh, musky scent of his cologne and his sheer presence. It was my first time being up close and personal to him, and could now appreciate the rippling muscles underneath his tailored suit. Even in my highest heels, I still had to tilt my chin up to look at him. I felt so small and feminine, and yet, fully in control of the situation. It was a new and intoxicating sensation.

Ignoring his question, I placed a delicate hand on his broad chest, and felt his heart pounding rapidly. In a soft purr, I said, "Stepbro, I know we're not going to prom but I'd still like that corsage."

"Uh, c-can I give it to you later?"

With wide, doe-like eyes, I looked up at the now-sweating Brad. "Please? I'll do anything you want..."

Gripped by a sudden, carnal urge, my hand involuntarily slid down his hard chest towards the large bulge in his pants that he was unsuccessfully trying to conceal. Brad tensed up, but didn't say anything.

"...I'll even help you with your little problem." As I wrapped my slim fingers around the tent formed by my stepbrother's throbbing erection—the first time I had touched a penis other than my own—I first marveled at how warm it felt even through the smooth fabric of his pants, then at how fucking huge Brad was down there. I could barely wrap my entire hand around his cock. Licking my lips unconsciously, I said, "Or should I say, big problem."

"W-what are you doing? This is going too fa—"

With my other hand, I pressed a finger to his lips. "I see the way you've been looking at me, Brad. Just relax and let your step...sis take care of you."

I felt his cock twitch in my hand as he tried to stifle a groan. He clearly wanted this. And so did I. It was as if I was living out every stepsibling porn I had ever seen, except I had never thought that it would be in the role of the hot, nubile stepsister!

Slowly, so as to not startle him, my hand unzipped Brad's fly. My eyes were locked on his as he stood petrified like a deer caught in headlights.

No longer constrained, my stepbrother's fully erect penis sprang forth from its prison, poking me in the waist. I gave a girlish gasp as the girthy ten inches left a sticky trail of pre-cum on my dress.

I caught a faint whiff of the musky scent emanating from Brad's huge cock, and was suddenly glad that I had securely taped my own small penis back between my legs, otherwise a decidedly unfeminine tent might have formed under my dress.

Before I could second-guess myself, I dropped to my knees, thankful the plush carpet protected my smooth, bare legs. At this, my stepbrother's shaft twitched in my hand. I could only imagine what was going through his mind at that moment. Within minutes of discovering that he had a sexy step-"sister," she was on her knees in front of him, poised to deliver a blowjob with her luscious, red lips.

I opened my mouth and brought my head closer to the bulbous tip of Brad's cock. He gave a small moan, abruptly giving me a naughty idea.

"Do you want your stepsis to suck your cock, Brad?"

"H-huh?" He had never been a quick study, but in this case I couldn't blame him. Things were rapidly spiraling out of control for both of us.

"Say you want Jennie to suck you off, baby." It was strange hearing my girl name coming from my lips, and even stranger to realize I had unconsciously raised the pitch of my voice and reduced the timbre to a feminine, breathy whisper.

"I, um..." Brad mumbled.

"Come on, stepbro, say it. We both want this but I need to hear you say it." I batted my eyelashes at him as I bit my lower lip coyly.

My stepbrother gulped, and his cock twitched in my hand again. I allowed myself a small smile because I knew he never really stood a chance against my feminine wiles.

"P-please suck me off, stepsis." He sensed that I wanted him to play along, and said exactly what I wanted to hear.

Before he had even finished speaking, I had wrapped my red lips around his swollen cock and gotten my first taste of a man's pre-cum. We both moaned in unison. Even though I was a virgin and had never had my own dick sucked, must less sucked off another guy, it didn't take a rocket scientist to figure out what felt good. I swirled my tongue and bobbed my head slowly, savoring the sensation of my stepbrother's shaft sliding along my lips. Faint red lipstick marks marked how much of him I had taken.

In the corner of my eye, I saw myself in the dresser mirror: a slim, gorgeous blonde, makeup and hair exquisitely prom-ready, mouth stuffed with cock. It was hotter than any porn I had ever seen, because the sexy slut on her knees was me.

I was so aroused at the sight that my free hand went of its own volition under my dress to jerk myself off, forgetting that my limp cock was still securely taped back between my legs. Ugh. With no other option, I began rubbing the tip in circular motions, like a girl playing with her clit. It felt good, but something was off. Hesitantly, I pulled the gusset of my panties to one side and inserted my middle finger into my tight asshole. Oh, fuck, that feels amazing. I had never been bold enough to play with my ass, but I was feeling overwhelmed by the feminine sensations of being penetrated in both holes

I renewed my efforts on Brad's monster cock, slurping loudly as I aggressively shoved his meat deeper down my throat, suppressing my urge to gag. His hands hesitantly drifted onto my head as I felt him match my bobbing head with thrusts of his own. I knew my wig was securely glued down so I let him grab my hair as he began fucking my face in earnest. I had seen enough porn to know how hot that looked from his point of view, and I wanted to arouse him. His unrestrained lust was turning me on even more, and I inserted another two fingers inside myself, further stretching out my sphincter.

"Your mouth feels so fucking good, Jennie," Brad groaned, as his thick shaft slid in and out of my throat. I looked up at him and gave a little girly moan of appreciation as involuntary tears began to streak my mascara. Oh well.

Abruptly, he closed his eyes and tensed up, and I felt the cock in my mouth throb with urgency. He was going to cum. But I wasn't done yet, not even close.

Slapping his hands away from my hair, I spat out his dick and stood up in one motion, teetering briefly on my stilettos.

"Hey—" he protested.

Without letting him finish, I grabbed his cock and pulled him towards my bed. His mouth snapped shut as he followed compliantly like a baby elephant. When we got to the edge of my bed, I released his manhood and—locking eyes with him through my long lashes—slowly reached under my tight dress with both hands and slid my red panties down to my knees.

"Oh fuck..." my stepbrother mumbled. His cock, glistening with saliva and pre-cum, twitched in anticipation.

"This is my first time, so you'll have to be gentle, okay?" I whispered shyly.

I turned around and sensually crawled onto the bed, arching my back and presenting my hairless, puckered sphincter to my stepbrother. My heart pounded as I wondered if he would take up the invitation. A blowjob was one thing, since he could easily pretend I was a real girl, but now there was no way for him to not see the tip of my limp cock taped between my legs. Would this be "too gay" for him? I suddenly wondered if I was in for the beating of my life.

But Brad didn't hesitate.

Before I could even brace myself, he was guiding his wet cock into my eager little hole. Even though I had been stretching it out, my poor anus was not prepared for my stepbrother's sheer girth. I yelped in pain as he grabbed onto my waist with both hands and began pushing. My hands desperately clutched the sheets and I squirmed against his grip as I began regretting my rash decision.

After what felt like an eternity, the tip of Brad's cock abruptly slid inside of me with a pop, and I felt my strained sphincter securely wrap around his relatively narrower, but still thick, shaft. It was no longer painful. Instead, I gasped in ecstasy as a deeply fulfilling sense of pleasure permeated my entire being. It was completely unlike the brief spurts I had experienced while jerking off in front of a computer. Instead, an almost spiritual release threatened to overwhelm my synapses as I both experienced the rapturous feeling of being penetrated by a powerful, muscular man.

Oh my god, my stepbrother is fucking me.

That was the only thought my lust-crazed brain could process as Brad began pumping his hips, shoving his meat deeper and deeper inside me. With each thrust, his thick shaft would rub against the tip of my taped-back dick, sending jolts of pleasure up my spine.

Firmly impaled on his cock, I couldn't have escaped even if I had wanted to. Not that I did. It simply felt too good. Too right. I flipped my long hair back and moaned in girlish pleasure. The sound set Brad off as he increased the pace of his frantic thrusts. Eventually, I both felt and heard my ass cheeks clap against his hips as he fully bottomed out inside me. I was strangely overcome by pride, knowing that I had taken the entirety of my stepbrother's huge manhood.

"You're so fucking hot, Jennie," he grunted. "I'm gonna cum soon."

My straight, jock stepbrother was about to cum inside me. Me. The sheer taboo of it all, combined with the indescribably delicious sensation of being fucked as a girl, was too much. As his cock rubbed against the tip of my mine for yet another time, I began spasming in orgasmic pleasure as cum dribbled out of my limp "clit."

"Fuck, Brad, I'm cumming!" I gasped.

"OH FUCK!" my stepbrother groaned, as he collapsed on top of me, pinning me against the bed. I felt the massive rod in my ass pulse violently as a hot stream of semen filled my bowels. We both panted loudly as I instinctively clenched and unclenched my anus, massaging his cock and milking the last drops of his seed.