Incest Seduction/Let mom handle this
You lock eyes with your mom, silently pleading with her to do something. You've been riding a freaky rollercoaster this morning and you're far too horny to think straight so you hope mom can take care of this.
“Perfect! You're back!" she warmly welcomes your brother. You let out a brief sigh. “Can you come here a minute, baby? We could really use a hand." Mom is slowly rubbing her hand across your midsection, right below your breasts. "...or maybe two."
“Oh-kaaay," replies Zachary, cautiously eyeing your prone naked form.
“Poor little Kimmy is still a growing girl," starts mom, “But she's having some trouble."
Zack looks you over. “Trouble with what?"
"You see, it's about her chest." Mom moves to one side to guide him closer to the island. "I'm afraid she's... just too small."
"Mom..." you groan quietly. She doesn't need to remind you, or anyone for that matter. Padded bras can only do so much, and they can't do anything when you're naked.
Mom pulls your knee aside and positions your brother so he's looking down the length of your body from between your legs. "Yeah, um... she's still young, right?"
Mom takes offense for you. "She's 14!"
"And 13 like a month ago," notes your brother.
"Exactly! She should be blossoming, but our little flower is still just a bud."
"Ugh..." you utter, rolling your eyes.
"It's alright," mom pats her hand on your pelvis, resting it there afterward. "I know of a few tricks but Kimmy's very shy. We just need someone who can rub her for a while."
You throw your hands over your face to hide your shock and embarrassment, peeking out between your fingers. This is where she's going?
"She needs... what?"
"Stimulation, Zachary. She needs someone to squeeze her, play with her nipples, that sort of thing." Mom cuddles up to Zack, her hand shifting across your crotch. "I bet you have plenty of experience with that by now, my big college boy."
She slips her way under one of his arms, pinning your leg between them. "Mom, I... why can't she do it?"
Mom pauses. "Why can't she...? Have you ever tried to tickle yourself? It just doesn't work! No, it has to be someone else. Your father is busy with breakfast, so that leaves you!"
"Dad? Uh... does it have to be a guy?"
You take in a short gasp when you feel something rub your slit. With her hand resting so close to it, Mom is surreptitiously playing with your swollen vulva, leisurely thumbing your lips.
"Yes, of course it does, silly!" laughs mom, cuddling against Zack. "Don't think about it, baby. It'll be fine. I know old wives tales are hit and miss, but I think this is worth a try!"
He stares down at your meager chest with apprehension. "I guess so."
"Oh, and just between you and me," she says directly in front of you without lowering her voice in the slightest, "if I were you I would explore her body a little. Best to get her in the mood, have a little fun, activate those hormones. We need to get those juices flowing!"
"I'm right here..." you sigh, nearly a whisper. Somehow you sound much more seductive than you intend. You immediately blame mom. What's she's doing to you is... actually, it's really nice. Her touch is gentle but firm. It's more than a tease but not fully satisfying. You clench your bum, raising your hips a little. As if you weren't horny enough.
"So, uh... how long does she need this for?" Zack asks clumsily. He scratches the back of his neck, reluctantly accepting his task. Your brother looks so hot with his arm flexing in the air so casually.
"Hmm, I'm not sure. She needs a lot of help. Breakfast isn't long now... although I suppose it could be. Yeah, it's too hard to say. You just take your time. Make sure you give her your most rigid attention. I'll let you know when the two of you can come..."
Mom suddenly slides her palm onto your pussy, splitting your sex with her thumb. The tip of her intrusive digit pokes at your needy entrance. You can't help but moan aloud, not because of her sudden advance but because she stopped short of pushing inside you.
"...for breakfast!" she finishes cheerfully. After a peck on your brother's cheek, mom spins away only to hang giddily off of daddy's shoulder.
Once again a conflicted pool of arousal, you roll your head to find Zack staring at you.
"Sooo... you're very naked. That's new."
You grin a little. Then scowl. Is he making fun of you? "I thought I looked good naked."
"Well, I mean... sure. That's not really..." Zack is getting flustered the longer he stares at you. It's kinda cute. "Look, I don't think you need me. You can do this yourself."
"No! I can't!" you quickly reply. Not if you're going to win mom's bet anyhow.
Zack seems a bit surprised by your insistence. "Seriously? You really want me to do this?"
"Yes. Grope me, then fuck me," is what you want to say. The forbidden words get caught in your throat. You can't tell your brother just how much you want him. Instead you slowly spread your arms, sliding them across the island until they meet above your head. Stretching your already slim figure opens up your body completely to your brother. If you could translate 'fuck me now' into a pose, this would be it.
Zack glances at mom and exhales heavily. "Okay. This is crazy..."
You're okay with crazy if it results in Zack willingly fondling your body. You hold your breath as your own brother reaches over your nude form and plants both of his hands atop your chest. You shut your eyes tight, hardly able to process the sight of your eldest sibling grabbing your tits. Immediately you worry that he won't like this, that it's too weird... that you're too flat. You have a bit of shape but you're barely sporting an A cup. Laying down and stretching out like this isn't making them look any fuller either. If anything you look even flatter like this. But Zack's warm hands begin to softly knead what little flesh you can offer him all the same.
Zack is right. This is crazy. A stupid, insane, amazing kind of crazy.
You suddenly exhale, forgetting to breath for a moment, your chest rising and falling quickly under Zack's steady squeezing. The desire to scream out for your brother to defile you in front of your parents is so great that you purse your lips together for fear of uttering it. But the look on your face, harshly cringing, sends a different message to Zack.
"I'm sorry," he offers. "I guess Mom did try to warn me. Here."
Zack's hands slide downward, quickly finding your hips. Gripping your sides, he pulls you toward him. It's only a few inches that he drags you closer to him, but only your wildest dreams had him manhandling your body like this. The repositioning brings you to the literal edge of the island, your bum nearly hanging from its precipice. This also forces your legs further apart, the inside of your thighs spread open by the outside of Zack's.
"Hopefully this helps."
As your brother's hands get to work you promptly let go of your tense, anxious pose. His hands roam freely, caressing your sensitive, stretched, slender midsection. You can envision his hands coated in sensual oils, lubing up your body just before ravaging you. It's likely only slightly less enjoyable with his non-lubed hands, although now you wonder what getting covered in oils would feel like. But you're not complaining. It's utterly amazing to have your brother brush a hand down your leg, to feel him push upwards from your pelvis, glide over your belly button, skirting between your breasts, graze across your collar bone, then rub up the side of your neck into your hairline. You can feel your nipples stiffen and ache, begging to be touched while Zack teases you across your entire body. He only glances past your chest on his way to other patches of skin he hasn't fully massaged yet. He's so attentive and considerate and careful with your vulnerable body. Even though you've known him your entire life, this prolonged and most intimate contact with him makes you feel like he's touching the very essence of your soul.
You never though having your brother rub down your naked body could be this downright incredible. It's also downright aggravating. You're pretty sure that's what mom was aiming for when she suggested this to Zack. Still, you manage to let him explore you for a full two minutes before you really start to lose it.
Well and utterly turned on, you wrap your legs around Zack and press your heels into the backs of his thighs, pulling him into the counter. You grab onto his wrists at the same time the bulge in his pants bumps into your dripping wet slit. You're so fucking happy your brother is tall right now. Bumping into you causes your brother to jump a little and pull his hands off your body. You calmly redirect them back to where they started, centered on each of your tits. Having his palms press down on your nipples makes you squeak a little. You've never been hornier in your life.
"H-here," you state shakily, "...is better. Keep going."