There was a heat wave in early August, and the air conditioner was broken.  Kyle and Monica’s cash supplies were so low that a repairman was out of the question, and so all they could do was endure the heat as best they could.  Kyle awakened in the night, finding that he’d kicked all the blankets off in his sleep.  The windows were open, and outside all was calm except for the soft night-song of frogs and insects, and occasional cars passing on the street.

His erection was painfully intense.  Even his baggy boxer shorts – all he had worn to sleep that night – pressed uncomfortably against it.  Absently he reached out, intending to give himself release before drifting back to sleep…but decided his need to urinate was greater for the time being.

It took several minutes in the bathroom for his manhood to deflate enough to use the toilet.  He washed his hands, splashing water on his face, and walked back toward his bedroom.  He felt better than he had in days.  Perhaps tonight he’d be able to fall back asleep without a self-pleasure session.

The door was open as he walked past his parents’ room – now Monica’s room.  He was resolved not to peek on her, knowing it would only cause trouble, but a faint white glinting caught his eye, made him pause.  Monica was asleep, covered by only a flimsy top sheet, partially see-through in the pale moonlight.  Her enormous feet stuck out from underneath, hanging over the edge of the bed.  From the way the sheet lay on her body, it was obvious she was naked underneath.  The gentle sound of her snoring came, rhythmic and even. 

Standing on the bedside table, seeming to glow with their own internal light, were four completely full bottles of milk.

His mouth instantly began to water.  He’d been dreaming of another taste for weeks – a swallow, or a drop even would be enough.  Four whole bottles…!  His mind reeled at the thought of such a bounty. 

Slowly, Kyle crept into her room.  The floorboards creaked under his feet, but Monica did not stir.  There was no way he could get away with this scot-free – even in his irrational state of excitement he knew that.  Monica would notice the missing milk tomorrow – if she didn’t wake up at the sounds of his passion.  He would go down to the basement, he reasoned.  There was a spare bed for guests down there, and who cared if it was dusty?  He could shut the door, bite down on his belt…she would never hear him.  Tomorrow she would tease him for his theft, but that wasn’t so bad, was it?  No, not so bad at all.

He was close now, so close.  Monica’s smell was strong, already reawakening his flagging erection.  And now the bottles were within reach.  He could only carry two…but two would be more than enough.  He lifted them, one in each hand, and stared at them longingly.  They were room temperature – probably hours old by now if she’d milked before bed.  He didn’t care.  The temptation of them, now that he finally had what he had lusted after for so long, was too much.  He’d have a sip now.  Just a sip.  The rest could wait until he was downstairs.

It was creamy, delicious, better than he could have possibly hoped.  It was almost as if Monica’s growth over the last weeks had somehow sweetened it, intensified its flavor.  A sip became a gulp…then another, and another.  Before he knew it, he had drained half the bottle.

His cock swelled, his body tingled from head to foot.  The feeling…he had wanted it again for so long…oh God, it was more than he could handle!  He knew at once that he was going to moan, that it would not be a quiet sound.  He knew it would wake his sister, that he would be caught in the act.  He swallowed, inhaled, prepared to give himself away – and in the instant before he did, he saw the twinkle of Monica’s eyes in the moonlight, even as she still pretended to snore.  She was awake.  She had been awake the whole time.

His moan was loud, and guttural, and lasted long enough that Monica had plenty of time to sit up, to cast aside her sheet, to set her feet on the floor and regard him fondly.  When he had finished, she lovingly stroked his chin.  “Was it good, little brother?  I wondered if I might have a certain little visitor tonight.  My bait was too much for you to resist, huh?” 

Her finger caught a stray drop that clung to the corner of his lip, pressed it into his mouth.  Another little surge of pleasure came, and with it, another small moan.  The tingling kept getting stronger, making it almost impossible for him to stand.  He wavered, holding himself against the bed, using both hands for support.

Grinning, Monica sauntered across the room, closed the door, turned the lock with a solid CLICK.  Kyle followed her helplessly with his gaze, finding himself utterly transfixed by her.  God, she was so big.  How had he become used to this?  It was as if he were noticing for the first time.  The top of his head barely came to her chin, far lower than his memory said was right.  In the tricky light of the moon, she seemed to be getting bigger each time he looked at her.

“I’ve known you wanted my milk for soooo long,” she purred, returning to sit on the bed.  She positioned herself with her legs spread on either side of him, holding him in place with her knees against his hips.  “Ever since that wonderful night when I left you a taste, I’ve seen it in your eyes.  The way you’ve watched me every day.  The way you’ve called my name every night.”  She chuckled.  Kyle wished that he could crawl into a hole and die. 

He moaned again.

“What’s absolutely silly,” she went on, catching him by the shoulders, turning him to face her. “Is that you could’ve had as much as you wanted – if only you’d bothered to ask.  I’ve WANTED to share with you, Kyle.  Oh yes.  And you wouldn’t have needed to settle for stolen sips of luke-warm leftovers.”  She cupped both of her massive breasts, each nearly as large as Kyle’s head, and bounced them suggestively.  “I would’ve let you drink…from the source.  Oh wow,” she exclaimed suddenly, covering her mouth to suppress a giggle.  “I didn’t think it’d be THIS effective.”

“W-why?”  Forming words was almost impossible now.  His lips felt as heavy as lead, his mind dull.  His dick throbbed and ached, pointing directly at Monica through his boxers, as if begging for her attention.

“Why didn’t I tell you?  Why did I tease you and torment you with something I knew you wanted OH so bad?”  She winked, then abruptly leaned down and planted her lips over his.  The kiss was all-encompassing, overwhelming.  It was all Kyle could do to keep his balance as his juggernaut of a sister forced her tongue into his mouth, gently probing, exploring.  It felt amazing…almost enough to give him the release he so badly craved.  Almost. 

“Obviously,” Monica went on, as she finally broke the kiss.  “Because you’re supposed to ASK for the things you want.  You’re a big boy Kyle.  Or well, you were.”  She laughed again.  “Look at you still going!  Maybe I shouldn’t have let you drink so much after all.”

He looked up at her, completely missing that moments before his gaze had been several inches above hers.  His mouth hung open stupidly.  “What?” he panted.

As a reply, Monica held up one finger.  Gently she drew it down over his stomach, toward his crotch.  Another long, low moan came…God, everything she did felt so good!  When she reached his boxers, however, she merely gave the elastic band a tiny nudge.  To his surprise, the garment easily slipped down his waist several inches, balanced for a moment on his erection, then slipped away to pool at his feet.

He stared down at himself, his manhood alarmingly hard, twitching faintly in time to his heartbeat.  He looked up at her again to ask silently for explanation – and again, she looked bigger than only a moment before.  Something wasn’t right…he couldn’t think…he couldn’t think….

Monica cleared her throat.  Very deliberately she grabbed him, made him face away from her.  There was a floor-length mirror across the room, and as he stared at his own reflection, Monica leaned down, her massive breasts plushing warm and heavy against his back.  She grinned, and her image in the mirror waved at him.  “Hello there, LITTLE brother.  Enjoying the view?”

“I’m…s-smaller!” he gasped.

She laughed a deep, rich laugh.  “Not just smaller, cutie – shrinking!  As in, present tense.  Here, watch.  Stand still.”

She took his hand, covering it completely with her own, and made him lift as high as he could.  Second by second he watched as it sank lower…and lower.  He could actually SEE himself shrinking.  Monica was right.  The perspective was so strange, watching his reflection get smaller, seeing the angle of reflection – and thus his entire reflected view – change as his head sunk lower.  And as his body dwindled he could see more and more of Monica behind him, as if his body were deferentially getting out of the way for her. 

“It’s been so sexy for the last few weeks,” Monica was saying behind him, as the two watched Kyle shrink.  “Getting to tease and rile up my adorable little brother, knowing something you didn’t.  I saw you shrink, you know – the first time you snuck some of my milk.  I mean well, I noticed it afterward, right away.  I had to do some research just to convince myself it was possible.  I think you probably lost about an inch.

“The best part was, you wanted MORE.  You were going to sleep every night, moaning about my milk…touching yourself.  I was jealous of that last part, I admit – that you were allowed to cum as much as you wanted, and I had to stay celibate.  I cheated.  A few times.  Did you notice?  I was so pent up I came really really hard, and it made me grow a lot.  I don’t think you minded, the way you were looking at my big breasts, the way you practically drooled when I would stand, towering over you, sooo much bigger than you.

“And now…as small as my milk is making you…I get to be much, MUCH bigger than you, don’t I?  I knew what would happen of course, if…WHEN you drank more.  I certainly didn’t expect it would shrink you THIS much!  I had hoped for a few more inches, to put you properly on the petite side of things but…gosh Kyle, look how tiny you’re getting!  You’re probably not even five feet tall anymore!  Mmm but that adorable little cock of yours doesn’t seem to be complaining…just look how happy he is!

“Oh wait, I’m sorry.  Am I the one that’s doing that to you?”  Monica’s tone was sympathetic as she pointed down at Kyle’s manhood.  It had turned a shade of angry purple, and was bobbing up and down frantically as she spoke, as if nodding in agreement.  “Here, why don’t I help you with that?”

Monica gently gripped his cock between the tips of her thumb and forefinger, and with a feather-light touch massaged her way up and down its length.  “You know Kyle,” she went on, speaking loudly enough to be heard over his frantic gasps and howls of pleasure.  “This is the first time I’ve actually seen you shrink in person, so you’ll forgive some wild speculation on my part.  I’m beginning to think it happens immediately after you drink, in the first few minutes.  The, shall we say, pleasurable side effects last quite a bit longer.”  She ran her thumb over the ultra-sensitive area just beneath the head of his penis, and giggled as his body went limp, his arms and legs spasming uncontrollably.  “Quite a bit longer, yes.  In any case, I say this because it looks like you’ve already finished shrinking.”  She leaned into him, settling his head between her breasts, and made him look up at her.  God, the smell of her…!  “Would you like to know how small you are?” she asked in a babying voice.

In truth, the answer terrified Kyle.  Yet through his erotic haze, he perceived the answer Monica wanted.  With her now massive size advantage, and the way she was making him feel, he had every reason in the world to keep her happy.

He nodded.

“I’d say you’re just a teensy…widdle bit over five feet tall.”  She punctuated the news with a powerful squeeze of his groin.  Kyle’s vision darkened, and as he began to collapse Monica reached down and scooped him up.  With a little grunt of effort she hoisted him into her lap, and promptly set her attention back to his cock.

“Now I know that seems quite small,” she went on in a placating voice, pumping him closer and closer toward his inevitable orgasm.  “But think of it this way – I used to be much, MUCH shorter than that, and I got along just fine.  Partly because I had you to take care of me, of course.  To protect me, to take care of my every want and desire.”  At this she paused in her narrative long enough to kiss him long and deep, her giant lips pressing hungrily against him.  “I’m very grateful for that by the way, and I think it’s high time I return the favor.  At my size, I’m going to be a MUCH better helper than you ever were.  Won’t I?  Yes I will…yes I will!”

Her grip tightened on his manhood.  The sensation took on a different tone…more purposeful, more deliberate.  “Kyle,” she growled.  “Do you want me to make you cum?”

He nodded submissively, staring up at her with wide, blank eyes.

She squeezed him once.  “Call me big sis.  You never do that…and I think you’ll be saying those words quite a bit more soon.”

It took him three tries to articulate the words.  “Big sis,” he husked.

“Good boy.  Now say, ‘please make me cum, big sis.’”

“Puh…puh….”  He swallowed.  When he spoke the words came out in one long high pitched screed.  “Please make me cum big sis!”

She stroked him faster now.  “Pretty please make me cum with sugar and ice cream and a cherry on top.”

“Pretty…pretty please…prettyyy ahhh!”

Kyle came.  The initial spurt flew high in the air, many feet over the top of Monica’s head.  She cooed to him, stroking him, milking every last drop of his jism from him.  When at last he subsided she held him to her chest, gently rocking him back and forth, still stroking him.  “There now.  I bet that felt soooo nice, didn’t it?  You’ve wanted big sis to do that for a LONG time now, haven’t you?” 

Chuckling, she released his cock, and lifted her cum-covered fingers to her lips.  “You know what I’VE been wanting to do this for so long?” she whispered.  “To taste little Kyle-y-poo.  Your sheets absolutely reek of cum you know, and I’ve been loving that smell all summer long.”

Making sure she had his attention, Monica purposefully licked herself clean, cat-like and seductive.  She watched him mischievously as she did, and grinned as his cock immediately began to swell back to full strength again.  “Aww!  Did my milk help your little penis get hard again sweetie?  That’s very, very good Kyle – because I’m not through with you yet.  Now, I want to talk about these silly rules we have about me touching myself…and about just how big I’m allow to get.”