Big Sister's Penis Shrinking Elixir

Big Sister’s Muggle Boy Penis Shrinking Elixir [incest][sph][Harry Potter Universe]

[excited] Hey little brother, get in here and shut the door.  You’re not going to believe this.  The potion actually works!

[pause]

What do you mean “what potion”?  The potion I told you about.  The one that’s supposed to make my tits bigger?  It works little brother.  My tits are huge now.  Do you want to see?

I’ll let you look, but no touching, okay?  Let me just pull off my witch’s robes and

[pause for effect]

…there you go little boy.  Your very own big sister’s double G magically engorged tits.  Aren’t they amazing.  I’ve never seen anything so perfect in my life.  I mean these beauties must weigh ten pounds each, and they don’t sag.  Not even a little bit.  These alone make all those years I spent in school worth it.  Thank god Hogwarts accepted me as their first ever foreign exchange student.  I’m sure the potions teacher at Illvermorny is competent and all, but I was taught by Professor Slughorn.  And he’s probably the best potions master who ever lived.  I’d never have been able to brew this stuff if I hadn’t studied with him.

Now I understand why they didn’t let us brew this potion at school.  I’d have driven those Hogwarts boys crazy walking around the castle with these monsters.  All those proper English schoolboys with lumps in their robes.  [giggles]  Kinda like that little lump you’ve got in your shorts right now.  What’s the matter little brother?  Are your big sister’s tits giving you a little boner? [giggles]

Its, okay little bro.  That’s why I wanted big tits in the first place. To make guys horny.  It’s a little creepy that they made my own brother horny, but I’ll just think of it as a compliment.  And speaking of things getting bigger, I’ve got another surprise for you little brother.  Guess what else this potion can do?

Well I’ll give you a hint.  If you were to drink this extra bottle that I made, then you’d have a much bigger tent in your shorts.

Yep, that’s right.  This potion makes boy’s dicks bigger too.  That’s why I made so much extra.  I know you’re embarrassed about your little dick.  And since I was using my magic ability to improve myself, I thought I might as well help you out too.

I know you don’t understand magic, and drinking a magic potion might seem a little scary, but I promise you’ve got nothing to worry about.  The potion is perfectly safe.   And it does more than just give you a big cock.  It’ll also give you extra hard erections and super powerful orgasms.  So, if you want big raging erections and the ability to spurt out buckets of cum…I think you should drink it little bro.  And do it soon while it’s still warm.   Do you want to try it?

Awesome.  I knew you’d give in eventually.  Now, take off your pants and get that little dick out for me.
I’m going to touch it okay?  I want to measure it with my finger to see how much the potion makes it grow.
Hmmm?  Right now, your penis just a bit longer than my middle finger.  See?  And that means it’s probably about four inches long.   And since you’re already hard, I assume that this is as big as it normally gets?
That’s seems about right.  You’re so horny little boy.  This must be a bit overwhelming.  Seeing your big sister’s huge tits while she touches your little dick is nice, isn’t it.

Now, go ahead and drink the potion.  I’ll keep my finger on your penis and we can watch it grow together.  It should only take a couple of minutes.

That’s right. Drink all of it little brother.  That’s a good boy.  Now, let’s watch.

[pause for a moment]

It should start growing any second now.

[pause for a moment]

Are you paying attention or are you looking at my tits again?  Try to focus little boy.  You can stare at my tits after…   Oh, look.  Your dick is starting to vibrate.

What the….

[pause]

This isn’t right.  Does that look like it’s getting smaller to you?

Does it feel different?  It seems like it’s getting harder but….it’s shrinking too.

[pause]

Oh my god.  It’s shrinking down below my knuckle.   Something must have gone wrong.  You did drink the whole bottle, right?

Calm down, I’m sure I can fix it.  Let me check the potions book again.  Maybe there’s a charm to reverse it or something.

[pause while she checks her book]

[mumbling]  “…..Stir ingredients over a small blue flame seventeen times clockwise, then fourteen times counter clockwise while humming a lullaby…..”

I did all that, and the potion worked perfectly on me.  Maybe there is something I missed in the notes.

[mumbling] “….potion works best on wizards, witches, and female muggles.  Under no circumstances should this potion be used on muggle male…”.

Oh shit!  Little brother.  I am so sorry.  I didn’t read this part.  It says that the potion shouldn’t be used on muggle males.

Little brother, I think I shrunk your dick.  And I don’t know if I can fix it.  The counter spell requires, and this is a direct quote, “acts of unfathomable sexual perversion”.   I don’t know what that means, but…I’m almost too scared to turn the page and find out.

Okay fine!  I’ll read it.  Keep your shirt on.  This is going to be bad, I just know it.

[mumbles]  “To reverse the shrinking effects of the ‘Plump Them Up potion’ on a muggle male’s penis, the nearest related witch..…[trails off]

Oh, you’ve got to be kidding me.  That’s just…disgusting.  It says that “…the nearest related witch family member must engage the muggle sexually within an hour of drinking the potion.   Only an act of loving incest has enough magical power to reverse the potion’s physical effects.”

Do you know what this means little brother?   I think it means that we need to have sex in the next few minutes or your penis will never grow back.   I’m the only witch in our family.  And that means…I have to be the one who does it.
Damn it.  Why didn’t I read through this before I gave you the potion?

I don’t know if I can do it little bro.  Do you think it’ll be okay if we don’t?  I mean, you already had a little penis to begin with.  It’s not like having a four inch dick is so much better than having a….what?  Two and half inch dick?   Most girls are going to be disappointed either way.  And I really don’t want to have sex with my own little brother.   So, let’s just forget any of this happened, okay?   You’re just going to have to accept the fact that you have a micro penis and learn to deal with it.  It’s not like you have a choice in the matter.  There’s really nothing you can do to change my mind.

No, don’t do that.  You can’t tell mom about this.  She’ll freak the fuck out.  God only knows what she’d do or who she’d tell.  I could get in so much trouble if anyone finds out I used a magic potion on a muggle.  Fuck, fuck, fuck.  I can’t believe I have to fuck my own….

Wait a minute.  It doesn’t actually say sexual intercourse.  It just says an “act of loving incest”.   Lots of stuff can be incest besides full sex.  Making out could be incest.  A hand job could be incest.  Hell, I’d even be willing to suck you off if it means I don’t have to fuck my own little brother.  We’ve got… I dunno…forty-five minutes before the potion is irreversible?  Let me give you a quick blow job and we’ll see what happens.  Maybe it’ll work.  And since it’s your first time, I doubt you’ll last very long.  If your baby dick doesn’t bounce right back, we’ll still have time to figure out our next step.   Wanna give it a try?

Okay, lay back in my bed and I’ll get down between your legs.

This is so weird.  I never thought I’d be in this situation.   On my knees about to suck a little penis.  And not just some random little penis.  It’s my own brother’s little penis.  But, I guess this is what happens when you don’t read all the instructions.

I hope you enjoy this little brother.  This is the only time I’m ever going to suck your tiny dick.  I’m only doing this because I love you…and because I don’t want to get in trouble.

[slow gentle sucking sounds for several moments]

Are you okay, little brother?  You look like you’re about to pass out.  Try to stay focused, okay?

[Slow gentle sucking sounds for a few moments]

That’s right little boy.  Watch my lips move up and down your tiny little dick.

[slow gentle sucking sounds for several moments]

You’re so lucky to have a big sister who loves you as much as I do.

[gentle sucking]

Most boys can only fantasize about being sucked by their sisters

[gentle sucking]

But you get the real thing.  And all because you have such a little penis.

[slow gentle sucking sounds for several moments]

Mmm.  Yes, little brother.  I can feel you getting close.  You’re leaking precum already…

[gentle sucking]

….and it tastes like….

[gentle sucking]

…it tastes like peppermint.  That must be from the potion.  I wondered why it called for three bunches of freshly picked mint leaves.

[slow gentle sucking for a few moments.]

That’s it little brother.  Do it.  Cum in your big sister’s mouth.

[slow gentle sucking for several minutes, she slows down even more and makes quiet moaning sounds as she enjoys the taste and swallows his cum]

Wow!  Your semen tastes good too.  It tastes like the chocolate from Honeyduke’s.

[Slow gentle sucking for a few more moments]

Good boy little brother.  I can’t believe your little dick squirted out so much.  I almost couldn’t swallow it all.  That potion must make you produce a ton of semen.  That or you really liked how it felt to have your big sister suck your little dick.  It definitely made you taste good.  Minty precum and chocolate semen?  The ladies are going to love you when you’re older.

Hopefully it’ll still taste like that if we manage to make your penis to grow back…which now that I look at it….nope.  It’s not any bigger.  It’s still throbbing and hard, but not any bigger.
It seems that in the magical world, blowjobs don’t count as incest.

[sighs]  I guess we know what we have to do now, don’t we?  I was afraid of this.

No, little brother.  Stay there.  I’ll get on top.  You’re still a virgin and I doubt you know what to do.  Just relax and let me do all the work.

At least your first time will be with someone who actually loves you, and who is great in bed.  I lost my virginity to a Hufflepuff in a broom cupboard filled with old feather mattresses and books about the dangers of teenage pregnancy.  He lasted about ten seconds, and then dashed out and forgot to pick up his wand.  He told me later that the broom cupboard disappeared when he went back to get it.  Typical for a Hufflepuff.  They have the worst bad luck.
But forget about him.  Let’s get this over with before I change my mind.  And we should probably kiss a little bit too.  This is supposed to be “loving incest”.

[deep kissing for a few moments]

Mmm.  That was nice little brother.  You kiss like true Gryffindor.  Well, a Gryffindor with a little dick, at least.  You’re not that bad for someone your age.

[kissing]

Now, are you ready for this?  You’re about to have sex with your own big sister.  I’m just going to lower my tight pussy down on your tiny little penis and…

[pause for effect]

…You’re in little boy.  Kiss me again.  Let me show you how much I love you, baby brother.

[deep kissing and gentle moaning as they have sex]

Oh, little brother.  I didn’t know a little dick would feel this way.  It’s so….perfect.  Like we were made to fit together.

[deep kissing]

And I swear I can feel it expanding inside of me.  It’s not stretching me out or anything, but its filing me up….and making me warm inside.  It’s like, your little penis is at home inside my tight pussy.  Like I’ve been incomplete all my life, until finally, you found your way inside me.  I’ve never felt this close to anyone before.  I’ve never felt so much…love.

[kissing]

I love you little brother.  And I love your little dick.  And I love the way it feels in my pussy.  I want you to cum little boy.  I want you to cum deep inside me.

[kissing and gentle moaning for several moments]

Your tiny dick is twitching little brother.  Are you gonna cum again?

[kissing and gentle moaning]

That’s it.  Cum for me little brother.  Let your sweet little penis erupt inside me.  Cum in your sister’s sweet pussy.  Be a good little boy and fill me with your cum.

[Kissing and gentle moaning for several moments as he cums inside her and she begins to relax on top of him]

Oh my god.  You’re still going, aren’t you?  I’m not even moving and your dick is still pumping me full of your cum.
No, it’s okay.  I like the way it feels.  Just keep kissing me, and enjoy the way my tight pussy milks your little dick.

[kissing for several moments]

That’s better.  Are you all done?

You’re such a good boy, little brother.  Let’s see if your penis grew back?
Stay still and I’ll climb off.

Hey look.  It worked.  Your little dick is back to its normal size.

Well, it’s still a little bit shorter than it was before, but only a half inch or so.  Maybe there are more instructions in the book.

[mumbles]  “for full penile regrowth…[trails off]

Okay, I found it.  It says “in order to maintain the restored penis size, incestuous copulations should be performed twice daily, once after sunrise and once after sunset, for at least five consecutive years.  Additional penile growth may occur if the muggle’s semen is swallowed directly by his incestuous lover during a regular regimen of multiple daily oral sexual favors.  The highest recorded growth rate observed was 1 sixteenth of an inch per year when oral favors were administered 10 or more times per day.  Data suggests that ingestion of the semen of a muggle (or squib) younger sibling is the world’s most effective contraceptive.”
Well, little brother.  It’s a good thing you like incest, because according to this I’m going to be fucking  and sucking you off a lot.  It’s going to take at least eight years for me to suck your little dick back to its original size.  And that’s at the minimum of ten blowjobs per day.  I suppose I could do it more often if you’re up to it.  And I guess you are because your little dick is hard again already.  Does this mean you’re ready for your loving big sister to suck your little dick again?

[pause]

Then lay back, relax, and prepare to be worshiped.  You really are lucky that I love you so much, little brother.   I wouldn’t do this for anyone else.

[slow and gentle sucking sounds for a few moments, fades into silence]