Incest Seduction/Find where Zack went
You can't stop thinking about your sibling. As much as anything you just want to be near him, but maybe you can find out more about what that means. So you wait as patiently as you can for enough of a lull in mom's continuous chatter to get two words in.
"Where's Zack?"
"Hmm? Well I wouldn't be surprised if he wanted to relax for a while. But he's probably checking on his laundry."
You get up and wander off rather abruptly before mom can trap you here any longer.
You don't make a beeline for the laundry room though. You want to make sure your brother isn't just hiding around a corner or something. He isn't in the dining room or living room. You check the guest bathroom on the main floor, but he's more likely to have gone upstairs for a shower if he wanted to freshen up. You sure hope not. You also notice that daddy's office door is closed. You're not allowed in when it's closed so you sigh and keep searching. You make sure to look everywhere you're allowed to go before you check the laundry room. It's not an arduous search or anything, you just want to be thorough. And maybe you wanted mom to be wrong, just to spite her.
Zack is indeed in the laundry room idly poking at his phone. He's still shirtless and leaned up against the dryer. His sweatpants are sitting low on one side teasing his pelvis. His hair is messy and he didn't shave this morning giving him just a bit of stubble. You could honestly jump him right now. You swear you didn't even notice how handsome your brother was until a couple years ago.
Since you have no innocent reason to come looking for him you just peek in through the doorway filled with uncertainty. Thankfully Zack catches you out of the corner of his eye.
"Are you coming in weirdo? Or you just a creep now too?"
With a playful scowl you glide into the room and park yourself next to your sibling. When he looks over at you the color drains from his face, looking slightly panicked.
"What's wrong?" you ask, concerned. Looking down you are reminded of the streaky white mess across your face and chest. The mess that he helped put there.
"Jesus sis, you can't just walk around like that! That's not okay."
"But I like being naked," you reply, purposefully aloof.
Zack starts to scold you but stops when he sees your smile. He's totally worried that the evidence of his incestuous sin is still painted on you like a billboard. Your whole family has seen it already and it hardly bothers you after having to give up on your shower so you lost any urgency to get rid of it but Zack looks stupid guilty, if not downright regretful. Your brother grabs a sock from a pile on the floor and hastily wipes and rubs at your face, cleaning as much of his spunk off as he can. He changes out for a new one to take care of your chest. He's a little rough but you stand perfectly still for him, allowing him to clear his conscience more than anything.
"Better?" you ask him after he steps back to inspect you.
"Um, yeah. You're good." Good enough anyway. Arguably you're nowhere near 'clean' but certainly clean'er'. Your skin still feels sweaty and you undoubtedly smell like a cum rag, but at a glance you look more like a normal teenager again.
Zack immediately goes back to his phone, trying to hide himself in it. You'd swear he was blushing. But neither of you are quick to open up and share your feelings. It's clear he doesn't want to. You're struggling just as much, but you want to try.
"We should talk... about stuff."
Zack glances at you. "Should we? I think we shouldn't."
"Why not?"
"That's just going to make everything weirder."
"It already feels pretty weird."
"Exactly."
"I'm not mad or anything," you try to assure him. But Zack has all sorts of gears grinding away already.
"But what was that? Dad... and mom... we all... see, it's too weird."
You lean to the side and lightly shove your sibling with your shoulder. "It doesn't have to be."
Zack turns and examines the two headed naked girl beside him. His eyes are penetrating, as if he can see right down to your soul. But can he see your love for him? There's a drawn out pause before he comes up with an answer.
"You really are a freak, you know that?"
He's got you there. "Yeah."
"Like, I totally nutted in your lap, and in your mouth, and... well y'know. But... that doesn't bother you?" You slowly shake your head. "I don't know sis. That's fucked up. We're fucked up."
"Yep."
Your simple admission catches him by surprise. He turns to look at you again and you offer a sincere warm smile. Frankly you're gushing over him. You matter to him. He really does care about you.
"So you don't mind that dad just fucked you? That mom ate you out?"
"No." You're such a liar. You're conflicted about all of these things, but you refuse to let that create distance between you and Zack.
"So... so I guess we're cool then?"
"Yes!" you reply more emphatically.
"Huh. When did you become such a freak exactly?"
You roll your eyes and smile. "I told you, this morning!"
Zack smiles. "You fucking love this don't you?"
To that you shrug, truly unsure. "I don't hate it."
"Damn. Your middle school really fucked you up."
"I guess so."
"Was all this really because of a dumb bet?"
You have to furrow your brow there. "Well... It's not dumb."
"This is a regular thing isn't it? Are you trying to lose these most of the time? Do you normally take it this far? It sure seems like you agree to some dumb bets."
Scrunching your nose, you cross your arms as if you have years of experience to draw upon. "I don't just take any bet. It's not like you can bet me to punch myself, or stop breathing, or-"
"I bet you can't get through the rest of the day without finding some other 'bet' to do."
You scoff at him. "Yeah? Well that's an easy bet to win!"
"So is it a bet then?" He pokes your arm but doesn't really expect you to answer. "Naw, you wouldn't last 5 minutes. I'd just challenge you to kiss me and you'd be done for."
You try to keep from blushing. Is he serious? He then throws his head back and laughs at how hilarious he is which instantly frustrates you. "Shut up!" He's just making fun of you now. Your brother is so annoying sometimes. Besides, you haven't taken that many bets. But thinking about them again reminds you of the one you can still lord over him. "Hey! Why aren't you naked?!"
"Whuh? What are you talking about?"
"I won the spatula bet, remember? You promised you'd get naked with me."
"Yeah? And I did. When you gave me that weird lapdance nut on the next bet."
You look down at your own very bare body then gesture back to your brother; not that he's well dressed, but he's not naked. "...well?"
"Well what?" He then realizes what you're suggesting. "Hold up. You can't turn that back on now! I was asking you how long it was for but you weren't answering!" Zack whines, as if he has a valid excuse.
"It was for however long I'm naked! Obviously! Now c'mon cheater! Or does shy little Zacky think it's too weird?"
Zack is about to say something then just sighs. With a shake of his head he bends over and strips himself right next to you. Watching his penis pop into view now is just as exciting as the first time. You just want to boop it with your palm, to make it bounce or swing a little. He isn't all the way hard like before but he sure looks primed. Half of his cock is pointing straight away from him while the other half slopes down. It's not as impressive or intimidating as when he's fully stiff. If anything it looks cute and a little silly. But you can already see it lifting itself higher.
Zack throws his pants in your face. "Are you happy now?"
"Yup!"
He shakes his head again, perhaps at himself more than you, then walks right past you, clearly trying to run away, intent on leaving you here. You won't have that! Throwing his bottoms aside, you hop and leap up onto your brother's back.
"Nope! I lied!"
"The fuck?!"
"I demand a piggyback ride for your cheating, cheater!"
Your arms are hooked over his shoulders with your knees pinching in at his sides. You're on him but not all that securely. Zack reaches back, grabs your ankles, and pulls them up so they're in front of him. He also hops a little to get you higher up his back, strapping you on like a backpack. But between opening your legs and rotating your hips you find your pussy parting before pressing against his back. You hadn't considered this but it makes you grin.
Zack turns his head to issue a warning. "If you fall it's on you."
You respond by wiggling yourself tighter to him. Zack then takes off, bounding and sprinting in short bursts. You shake and bounce against his back, constantly squirming and adjusting to stay on. You try to turn and lock your ankles as your feet shift across his pelvis, but you're distracted by something long and firm that keeps slapping your toes.
Zack zips by the foyer, past the den, through the kitchen, around the dinner table, out to the living room, and back. He runs for much longer than you expect him to, your feet being tapped by his flapping dick for most of that time. When he ends up in the living room again he falls back onto the couch with a sigh, squishing you behind him and pushing the air from your lungs. Thankfully the back of the couch is soft, because your brother's back isn't.
"Happy now?" he pants.
His dick has flopped up towards his stomach now that he's sitting, but it's not especially floppy. He's fully stiff now and your feet can tell. You maneuver your soles and toes to feel either side of his long shaft and get some sort of a grip on him. Your brother hardly reacts, his arms at his sides, panting away to catch his breath.
"No, but you are," you note, pressing your feet together.
"Well... what more do you want from me?"
"Nothing," you reply softly. "You can sit."
With the heat of his body radiating into you, your pussy pressed against his back, you slowly manipulate your brother's firm cock with your feet. You find it's really fun to be able to feel him like this, to explore him without seeing him. Doing it with your feet somehow makes it naughtier and more innocent all at once. Like you're not really touching him at all, but you're totally walking your toes along the ridge of his cock and rubbing his length with the arches of your soles.
You have to keep rotating your splayed legs a little to get all the range of motion you want over your brother and that incidentally means shifting and rolling your pussy against his back. In teasing your brother you end up doing just as much for yourself. The little bit of motion is perfect and you keep repeating small unnecessary movements to help build your own pleasurable sensations. You still feel so hot and sweaty, now nearly suffocating under your brother's body, but it's worth it so long as you can rub yourself against him while walking up and down his dick. Unfortunately Zack doesn't feel the same.
"Are you gonna stop?"
You've been going for a couple minutes now without interruption and he could totally stop you if he wanted. So you're not sure how to respond to that. "...no?"
"Alright."
Your brother shifts away just long enough to grab a nearby remote then sinks back into you again. He starts watching TV just like during your last bet, except this time it's harder for you to distract him from that with him effectively sitting on you. Stubborn as always, you keep grinding against his back and massaging his cock with your feet, but as the minutes tick by you get frustrated. You grab onto his shoulders and start shaking your body against his, which is hardly at all, but in doing so brace yourself enough to move your legs a little faster. How does he have so much self control? You want him so bad. You want to make him go crazy, to moan out loud, to shout your name. He still feels rock hard and you can feel some wetness on your toes but all you're really doing here is tiring yourself out and finding it harder and harder to breath.
"Are you gonna stop?" repeats your brother.
"Umph... make me..."
He stands abruptly, unexpectedly, giving you no chance to properly latch yourself onto him to hold him down, or be hoisted up, before he's upright again. You're a little taken aback by this. He turns to face you with his raging erection and you smile. When he doesn't smile back right away yours disappears. Then he lunges at you. He grabs your arms and you instinctively start to fight him.
Pushing and pulling you try to shove him aside so you could run away or at least not give him the high ground, but he works with you and uses your own momentum to push you down onto the couch. It's almost scary how trivial it is for him to pin your arms above your head. Your legs are still splayed out to either side and, as he drops down to hold you still and finish dominating you, his dick glances off your mound before bouncing up and hovering a few inches above it. You grunt and strain and buck your hips but he just holds you down. It's only now that he starts to smile.
"What is this?" he asks.
"I... I dunno. Aren't you going to...y'know, fuck me?"
He looks down at his erection then slowly up the rest of your body, his eyes narrowing as he reaches your face. "Make me."