Tags: [F4M][Futa][Incest][Brother/Sister][Handjob][Oral][Anal][Dick Growth][Measurements][Inflation][Vomit][Slight Reluctance][Cursing][Moans]

Synopses: You are a 20 year old, male, living with his parents and 18 year old sister. You are fully aware she is technically a hermaphrodite with a small, non-functioning penis. One day, she comes to knock on your door, asking for you.

{Knocking sound on door}

• “Hey bro? Are you in there?”

• “Oh, good. I’ve… got something I want to ask you about. Can I come in?”

{Opens door}

• “Thanks. I would ask Mom and Dad about this, but I’m a bit too embarrassed. Plus they’re not here.

• “They went to the store.”

• “Well, I wanted to ask about… penises. More specifically, about when they grow.”

(shy)
• “Because my… (flustered) I just want to know, OK?”

• “So penises don’t grow much in your late teens?”

• “I didn’t have very a dramatic puberty, so could it be happening now?”

(defeated)
• {sigh} “You’re really going to make me tell, aren’t you.”

(flustered)
• “Fine. When I woke up this morning, my penis was bigger than usual. Happy?”

• “I don’t know, maybe like an inch or two bigger?”

• “No, its not hard or anything. Just bigger. So could it be like a delayed developmental growth or something?”

• “Nothing else out of the ordinary. My boobs aren’t any bigger and I’m not any taller.”

(Shocked and bashful)
• “Wh-what!? You seriously want to see it? I- I...”

(emphasis on ‘your’)
• “I’m embarrassed, that’s what! I mean, would you feel if I asked to see your penis?”

(Begrudgingly understanding)
• “I guess that makes sense.”

• “Yes. Fine, I’ll show you.”

(To self)
• “I suppose you would need to see it to tell me if something was wrong.”

{Rustling of clothes being removed}

• “Wha- Why are you making that face?”

• “How big were you expecting it to be?”

• “Wait. Is it not smaller than yours?”

• “The same size? That’s good I guess. Anyway, how can you tell if something is wrong just by looking at it?”

• “M-Measure it?…”

• “Y-yea. I guess we would need a measurement to see how fast.”

• “Yea, A ruler would work.”

• “Need help finding it?”

{Drawer opening sound}

{Shifting paper sound}

• “Alright. Hand it over and let me measure it.” 

• “Looks to be... about 4 and a half inches long.”

(Skeptical)
• “Huh? Naa. I doubt it’s growing quick enough to be larger than when I first came in. Noticeably larger anyway.”

• “Really? My balls too?”

• “I don’t know. Maybe it’s possible.”

• “Like, I can’t really tell if it’s growing now because it was like half this size last night.”

(Embarrassed)
• “What? Compare our- ugh! That just seems weird. Why?”

(Mockingly)
• “Well, curiosity killed the cat.” 

(Reluctant)
• “Alright, fine. Just don’t tell anyone we did this. I mean it.” 

• “Hehe. Touché.”

(To self)
• “Jesus, I can’t believe my brother is showing me his dick.”

• “Th-that’s your penis? Uh, I think mine is just slightly bigger actually.”

• “You swear it was smaller a few minutes ago? Uhh, I don’t know. It might have been.”

(Upset)
• “Wait. A-are you getting hard!? Ugh, what the fuck!?”

• “That’s no excuse you perv! I’m your sister.”

(Panicked)
• “M-mine? Wha- what is happening? Mine is getting hard too?!”

• “Sh- shut up! Am I seriously getting a boner?”

• “No, this has never happened before.”

• “Oh my God. It really is bigger than yours.”

• “Not sure. Let me measure it.”

• “Whoa. Over 7 inches. This is crazy.”

• “The ruler? Sure, here.”

• “Yours is 6 inches even? So mine’s about an inch and a half bigger than yours. Wow.”

(Flustered)
• “How do you get a boner to calm down?”

• “Distractions? OK, let’s see. You have a shelf on the wall. There’s a baseball, a deck of cards, and a Yo-Yo on it.”

• “The blankets on your bed are dark blue with gray and black streaks across it.”

• “I- I think it’s working. My penis is getting soft again.”

• “More? OK, Um… Your computer is on and the LEDs are cycling through a bunch of different colors.”

• “Your cell phone is plugged in and sitting on your bedside table.

• “Wow. It’s not easy to get an erection to go down, is it?

• “Yea, I think I see your point. You really don’t have a say when your penis gets hard, do you?”

• “Sorry for calling you a perv.”

{Rustling of clothing}

• “I gotta go use the bathroom for a sec. I’ll be right back.”

{Door opens and closes}

[Pause 15 seconds]

{Door opens and closes}

• “K, I’m back. I see you threw on a pair of underwear.”

• “So, what could be causing my dick to grow?”

• “Could it is some kind of delayed or second puberty.”

• “The speed? How fast does a guy’s normally grow?

• “Years? Uhh. So mine is growing a bit faster than that.”

• “Again? I guess we can remeasure?”

{Rustling of clothes}

• “You think? My balls do seem kinda bigger.”

(Skeptical)
• “No. There’s no why they’re three times the size.”

• “Uh, you really don’t need t-... whoa.”

(Shocked)
• “OK... maybe they are. Wow...”

• “Wait, where are you going?”

• “What’s the baseball for?”

(Flushed)
• “Wha- Ah heheh. I guess they’re about the same size.”

(With shaky breath)
• “That’s really something.”

• “L-Like it? N-no. What makes you say that?”

(Sheepish)
• “Oh. M-my erection. Umm. Maybe I do a little.”

(Accusingly)
• “What about yours? What’s your excuse?”

(Puzzled)
• “T-that you like my size? S-seriously?”

(Baffled)
• “It actually turns you on that my penis is bigger than yours?”

(Hesitant)
• “Th-that’s weird. I thought guys hate it when someone has a bigger dick, especially someone like me.”

• “R-right, measuring. Where’s that ruler?”

• “Thanks. Let’s see how long-”

• “I-it’s past the 9 inch mark. That makes it 3 inches bigger than yours.”

• “How thick? Uh… 2 and a half inches wide.”

(Stunned)
• “Wow. The your tip doesn’t even reach the bottom ridge of the head on mine.

• “W-what!? You want to touch it?”

(Hesitant)
• “Mmmhm. OK, just make it quick.”

{Draw in a shaky breath}

• “It looks pretty big in your hand.”

• “I don’t mind. K-keep stroking it.”

{Quiet, soft moan}

• “This feels really weird, but...{second soft moan} good.”

• “I-is that precum… coming out of the tip? (nervously excited) Oh God.”

• “This is amazing. It’s throbbing so hard in your hand.”

• “Faster! Stroke it faster!”

• “Something… something’s happening!”

{Draw in a sharp breath}
• “Gyaah! Egh… Egh… Egh...”

{Draw in second sharp breath}
• “Agh… ha….. haaa.”

• “Wow! I-I’ve never felt anything like that before.”

• “Oop… S-sorry bro. I guess you got some on you, or rather, a lot on you.”

(Sheepish)
• “It’s much more than what you guys make, huh? Maybe I was pent up for my first time.”

• “L-let me get you a hand towel.”

• “No, I don’t need pants. Mom and Dad aren’t back yet, so its still just us in the house.

• “One sec.”

{Door opening sound}

[Pause 7 – 10 seconds]

{Flesh slapping sound fades in, becoming louder}

• “Hey, here’s a towel.”

• “Huh? Oh. It slaps against my thighs when I walk now.”

• “Wait, is it?”

(Shaky/excited) 
• “Wow. It’s definitely soft now and still bigger than your erection.”

• “Sure. Hand me the ruler again.”

• “Umm. The tip reaches seven inches if I don’t stretch it.”

• “Two inches wide.”

• “Yea, my balls are kinda huge, aren’t they?”

• “I’m guessing over four and a half inches wide. Maybe four and three-quarters?”

• “It’s hard to tell because they’re so round.”

• “I guess they do kinda look like grapefruits?”

• “It feels like my groin is heavier as I stand here.”

• “I can feel the weight move around when I sway my hips.”

• “Say, you’re boner hasn’t gone down since I first showed you, has it?”

• “You must really like it then. Who knew you would be so in love with your sister’s huge cock?”

• “If you could do anything with my dick, what would it be?”

• “No, be honest bro. I want to know.”

• “Oh… Uh-ummm. I wasn’t expecting that kind of answer.”

• “I thought you’d want to hold it, slap it around, or compare it to yours some more.”

• “NO! no. I-I don’t mind. Just never thought you’d want it in your mouth.”

• “Alright. I guess you should g-get on your knees.

• “It’s OK if you don- Tiahhh.”

• “God, I feel every bit of your mouth around it.”

• “It feels so warm on my cock.”

• “Y-your tongue...”

• “A-are you gagging? Was that the back of your throat I hit?”

• “Sorry. I guess it is kinda big for a mouth, huh?

• “Uh bro, I might be getting hard here.”

• “Your mouth’s getting tighter.”

(Moaning)
• “Hmmm... ugh... Aghh... 

(Pulls out of mouth)
• “Aghhhhh. Haa.”

• “Wow, It’s as long as your head!”

• “Where did that stupid ruler go?”

{Shuffling blankets sound}

• “Here!”

• “Uh, it’s just about too long for the ruler.”

• “Eleven and three-quarters inches long.”

• “It’s practically twice the size of your dick.”

• “I’m starting to wonder if it’s getting too big. This is kind of ridiculous.”

{Optional slapping against belly SFX}

• “And my balls…  They feel so heavy.”

{Groan/moan}

• “Huh? What’s with that look?”

• “What could you possibly want to try next?”

(Disgusted)
• “Wha- Ew, no. No way!”

• “That’s really gross and even if I did want to do it, (sheepish) there’s no way it’d f-fit.”

• “Show me what?”

[Pause 7 seconds]

(Shocked)
• “Wha- What the fuck is that?

• “Bro? Is-is that a dildo?”

• “Jesus that thing is huge. Why the Hell do you have that!?

• “You actually fantasize about women with giant dicks?”

• “Do you really use this thing? It’s bigger than any of MY dildos!”

• “O-of course I have some because I’m a girl. Guy’s aren’t supposed to have toy fucksticks, let alone one this big!” 

• “Uh… Hm. Yea, when held next to mine, I guess it does seem about the same size.”

• “How long is this toy of yours?”

• “Then that means… yep. My dick has officially reached the end of this ruler.

(to self)
• “A foot long.”

• “Really bro? You’re almost starting to sound desperate.”

• “Fine.”

• “I SAID FINE! I’ll do it.”

• “It does sound kind of hot, I will admit.”

• “Do you have lube?”

• “Heh, why am I not surprised. Perv.”

• “Yea yea. I’m joking, kinda. Anyway, hand it over.”

{Cap popping open}
• “Let me put some on.”

{slick, wiping noise begins}

• “Ya know, I’m actually getting a bit excited.”

• “This is the first time I get to fuck somebody using my dick.”

{slick, wiping noise ends}

• “Alright. How are we going to do this?”

• “Perhaps on the bed, laying on your side.”

• “Yea, then curl your bottom leg in and I’ll hold your other leg on my shoulder.”

• “A-Are you sure you want to do this?”

• “OK. I’ll go slow.

• “Eh...eh….it’s hard to get in.”

(skeptically)
• “OK”

• “Eghhhhaaaa! Hah hah hah. So tight!”

(Shaky voice)
• “You might be right. I think it is bigger than your dildo now. Should I stop?”

{Exhale audibly}
• “Alright… Hup Hmmmmph hmmphhhfuck. This feels great!”

(Panted breaths)

• “Still good? I’m not hurting you am I?” 

• “Then I’ll keep going.”

• “Hnggg. {moderate moans}

• “I can feel you all around me.”

• “You’re so warm and smooth inside. So tight.”

• “Hnnnng hnnnnnng hnnnng ha hah hah.”

• “A few more inches left.”

• “Ahhhnggg ahhhnggg. Hnnnngah! There!”

• “Y-yea. T-that’s my balls pressing against you.”

• “Because they’re about the size of your butt. Hehe.”

• “You look worried. Having second thoughts?”

• “Yea, I wonder how much I’ll cum too.”

{gradual, deep inhale}

• “Ehahhhhh.”
{faster, exerted exhale}

{slow inhale, then faster exhale as if thrusting in and out}
(Repeat x2)

• “I can see my- {slight moan} cock in your stomach. {Exhaling thrust}

{thrusting breathing}
• “God, I see it passing your belly button.

{thrusting breathing}
• “And my balls are- {moan} smacking your ass.

• “Fuck this is hot. (Ragged breaths.)

• “Yes! Take my cock!” 

{Faster inhales, exhales.}
(Repeat x4)

• “I’m close too!”

{moderately loud moan}

• “Ah yes!”

{louder moan}

{alternate moans and shallow breaths for each spasm}
(repeat for 4 to 6 spasms)

• “Your stomach! I’m filling you so much!

(repeat moans/breaths for 3 or 4 more spasms)

{shaky, gradually longer breaths}
• “Hahhhh hahhhhhh.”

• “Holy hell! That was- Hey, are you OK? You look like you’re sick to your stomach and about nine months pregnant.” 

• “Are you about to vomi-UGH!”

• “Ew ew ew e-eh? I-it’s white. What is…”

• “Is this m- This is my cum!”

• “God. You just keep vomiting up more and more cum.”

• “Let me pull my cock out.”

• “Hnnnggg… gahh!”

• “Fuck I’m huge now!”

• “Hey bro? Thanks for pushing me to do this.”

• “And sorry about the mess.

{loud slapping sound fading out}
(In distance)
• “I can’t wait to see how much bigger it gets.”
{Giggling}