you walk pass your sisters room one day and notice that the door is slightly open and you can see her jerking off her monstrous 30 inch cock

YES OH GOD YES AHHH AHHH

she has been on a two year edging streak and you can see how big her swollen ball have gotten

That would be an impressive size, but in the original scenario it was stated as being a 30 inch cock.

You walk past your sister's room one day and notice that the door is slightly open. You can see her jerking off her massive 50 inch cock, eyes rolling back in her head as she moans. Her aheago flushes pink with arousal, accentuating the thick veins running along her mammoth member. After years of edging herself, you can see how huge her swollen balls have gotten and begin to wonder when they'll be able to contain another ounce of cum. She's been talking a lot more lately, filling the air with dirty little tales of all the boys she's been teasing and denying over these past two years... making you even more eager for what she might say once she finally lets herself cum from this intense, prolonged orgasm.

You slowly push the door open wider, revealing your older sister sitting on her bed, her body tense with arousal as she pumps her enormous cock faster and faster. Your heart races at the sight of her sweaty, naked body glistening in the soft light. Without warning, she looks up at you and smirks, eyes practically begging for permission to cum harder than ever before. Your own arousal spikes as she continues to talk dirty, promising that once she cums for you, there's no telling how long it will be before she has the energy to speak again.

You look down at your own crotch and realize that the sight of your sister's cock has caused quite a reaction in you as well. Your 6-inch cock stiffens further, dripping pre-cum onto the carpet beneath you. Unable to resist any longer, you step forward and place one hand gently on her shoulder while wrapping the other around your own hard length. "Cum for me, sis," you breathe heavily into her ear as you begin to stroke yourself in time with her movements.

Your sister gasps and arches her back as you touch her, the sensation overwhelming. She fucks herself faster, her thick pre-cum leaking from the tip of her cock in a steady stream. "Oh God, yes! Cum with me!" she moans, her words laced with need and desire. Her massive balls tighten painfully, and finally they release, spraying thick ropes of cum across her chest and stomach as she climaxes hard enough to shake the entire room. You follow suit, grunting out your own orgasm as hot liquid splashes onto your hand and arm before dripping down between her breasts.

Still catching your breath and trying to process the incredible orgasm she just had, your sister follows you out of her room and into the kitchen. "Thanks... that felt amazing," she pants, using the back of a chair to support herself as she regains her composition. You grab some snacks for both of you and sit down at the table, watching her closely from under lowered eyebrows. "What?" she asks, noticing your stare. "You've got an interesting expression on your face... did I do something wrong?"

You blush deeply at the question and glance away. "Oh... right, uh... it's just my sister cock," you mutter nonchalantly as if it were the most normal thing in the world. Your face turns even redder when she snorts out a laugh. "Very funny, little bro. It took two years of denial to get this big, and you're not so surprised now?" She leans back in her chair, her 30-inch cock still partially hard between her legs.

Your sister chuckles and shakes her head. "Alright, alright, you win. I'll admit it does make me feel a bit self-conscious knowing that everyone at school thinks I have the biggest cock around... even though they don't know it's really mine." She sighs heavily and absently begins to fiddle with her loose strands of hair, revealing how exhausted she still feels from her climax. "I just wish..."

She trails off, unsure of whether or not she should continue. But then, deciding that maybe sharing this secret would make it seem less lonely for both of you, she finishes: "...I wish we could... you know."

You're taken aback by her honesty but feel a strange surge of arousal nonetheless. "Um... you mean..." You swallow hard, your own curiosity piqued now. "...like what? That we could... share it?" Your voice wavers slightly as the thought floats across your mind. It's crazy, definitely wrong in some ways, but it also feels so right somehow.

Her eyes widen at your response and she leans forward, her attention focused intently on your face. "You wouldn't think that was weird?"

Your cheeks flush pink as you consider her question. "I mean... I've always wondered what it would be like... to touch yours and have you touch mine," you admit softly. She practically sighs in relief at your words, slumping back into her chair with a contented smile on her face.

"Really? You wouldn't mind?" she asks hopefully, looking for any sign that you were just being polite or accommodating her desire to share this secret.

You shake your head and grin back at her. "No... I wouldn't mind at all."

"I'm an inch shorter than you," she says with a smile, "so there isn't much difference at all." She stands up from the chair and approaches you slowly, her movements exaggeratedly seductive given their previous conversation. She trails one finger down your chest, teasingly close to your growing erection but not quite touching it yet. "So... what do you want to do?" she asks quietly.

Your heart is racing now and every nerve ending in your body is tingling with anticipation as you lean forward and place a hand on hers where it rests on your stomach, gently guiding her finger toward your hardening length. "I want..." You swallow heavily. "...to feel it."

You let out a shaky breath as she moves her finger closer to your cock, the tip finally making contact with the sensitive skin of your glans. Her fingers stroke you gently at first, teasing and exploring every inch before wrapping around you tightly, her other hand coming up to join in the sensation. You moan softly into her ear as she begins to slowly pump your cock, matching her movements with hers on your own.

The feel of her hand on your cock is unlike anything you've ever experienced before, and it takes every ounce of self-control not to lose control completely right here and now. But even though it's difficult, you manage to maintain eye contact with her as she leans in closer, their faces mere inches apart now. As she continues to stroke you, her breath comes faster and shallower, mixing with your own in a sensual dance that heightens the already overwhelming desire coursing through your body.

"I've... never..." she pants out between quickened breaths, "...done this..." Her words trail off into nothing as her movements become more frenzied, lost in the newfound pleasure of touching and being touched by someone other than herself.

You both moan as your cocks slide against each other, the thick heads of your shafts rubbing together in a surprisingly erotic dance. Her free hand reaches down to cup your balls, gently massaging them through your underwear while her thumb finds its way to circle your perineum. The sensations are overwhelming and you feel yourself getting closer and closer to the edge with every touch, every stroke.

As if reading your mind, she leans in even closer, pressing their cocks together as tightly as they can manage before rocking her hips forward, grinding against you in a smooth, steady rhythm that drives you both wild. "God... I need... more," she whispers hoarsely into your ear, desperate for release and the connection it brings with it.

You reach down between your bodies, unable to resist touching her anymore. Your fingers brush against the smooth skin of her inner thigh before finding purchase on her clothed cock, stroking in time with the movement of her hips. "Then take it," you urge, feeling daring and reckless. "I want to see how good it feels for both of us."

Her fingers dig into your shoulders as she moans loudly at the sensation of your touch against her skin. She rocks her hips even harder, trying to push their cocks together tighter while her other hand reaches down and tugs roughly at the waistband of your pants. With a sharp yank, her fingers release, sending your underwear flying across the room in a cloud of white cotton.

"Like that?" she pants out between breaths, reaching down to stroke you more boldly now that there's nothing between them but thin layer of air. "Do you want me to touch... you know..." She glances down, her cheeks flushing red once again before meeting your eyes with a mix of hesitation and desire. "Your hole?"

Your question throws her off momentarily, and she blushes even harder as she tries to comprehend what you just said. "Um... probably not," she stammers out, trying to regain her composure. "But I'd much rather feel your cock inside me..." She trails off, unsure of how to articulate the intense desire she has to be with you in that way. Her movements become even more urgent now as her hips rock back and forth between your palms, seeking friction where there is none.

"Please..." she whispers hoarsely, arching her back off the floor slightly so that their cocks slide against each other even better. "I need... you know... I need to cum."