All that summer, Monica had grown somewhat more than an inch taller each day.  Her growth slowed to a crawl at once after the follow-up.  The scent that seemed to surround her constantly – the one Kyle now understood became stronger after each of her self-pleasure sessions – dropped to a dull background.  This came as a great relief, and for a time the two settled back into their old routine – Kyle taking care of her, while she sat quietly and enjoyed his service.

Slowly things began to change.  First, Monica insisted on helping with the chores.  On some level Kyle was sad to lose sole responsibility for the upkeep of the house, but he was happy to give her something to do.  He even went so far as to make a chore chart, using every color of magic marker in the house.  Monica called it a thing of beauty, and set to work straightaway on the vacuuming. 

Her taste in television shows began to shift as well.  She lost interest in her daily regimen of game shows and science documentaries, and began to prefer romantic comedies or psychological thrillers.  The common element, as far as Kyle could tell, was that most of these movies contained rather graphic sex scenes.  Considering the state of his sister’s hormones he decided this was tempting fate, and after a few days he put a stop to it.  Monica pouted.

Most troubling, however, was that Monica was excusing herself more and more frequently to milk.  This wouldn’t have presented a problem, if not for a rather awkward request Monica had made the day after her appointment.  She now insisted that Kyle come and stand outside her bedroom door during these sessions, “…so I won’t try and cheat.”  This was embarrassing enough on its own – never mind the sounds she made as she milked.  Deep, lurid moans of pleasure, so loud and sensual that Kyle suspected they were at least a little exaggerated.  When he’d pounded on the door and asked if she wouldn’t mind keeping it down, Monica had replied sweetly that she couldn’t help it – she was just too pent-up. 

After many days of worrying, Kyle decided that even the privacy of her bedroom door was too risky, if these milking sessions were as pleasurable as she made them seem.  No matter how embarrassing, he announced that he should actually watch her milk, “…because how do I know you aren’t cheating if I can’t see you?” 

Monica objected, but it was clear she enjoyed this turn of events.  She seemed to take great joy in his discomfort, slowly stripping out of her shirt and bra, keeping her back turned so he could see nothing but the outermost curve of her enormous breasts around the muscular line of her back, and the gradually filling bottle of milk.

A week after the appointment, Monica’s moods started to become unstable.  Sometimes she would angrily demand things of him – that he make such and such for dinner, that it was his turn to clean the bathroom when the chore chart clearly said otherwise, that he give her backrubs and foot rubs that would sometimes last for hours.

Other times, she was frighteningly affectionate.  Monica would almost sit on his lap while the two watched television, and once at the theater she’d absently placed her hand on his inner thigh and gently squeezed.  He’d been far too surprised to object at first, and once enough time had passed the thought of pointing it out became much too awkward.  Monica had left it there for the entire movie. 

It took him awhile to notice, but that distracting scent of hers had come back, stronger than ever.  He found it getting harder and harder to concentrate when she was around.  His train of thought kept derailing into disconnected, dream-like images of eroticism.  Thankfully, there were no restrictions on how often HE was allowed to practice self-pleasure – that helped to keep things tamped down.  Although when he did, his sister’s image had a disconcerting habit of making unwelcome appearances in his fantasies.  Each time he patiently pushed it away, as though training a stubborn cat to stay off the counter-top.

One night in early July, it was Kyle’s turn to wash the dishes.  Monica had just finished one of her supervised milking sessions, and was now reading in the other room.  Kyle had almost finished loading the dish washer, when he came across Monica’s bottle – with nearly a quarter inch of milk still standing inside. 

He stared at it for a long time, with the slowly dawning understanding of why this struck him as such an odd sight.  Monica always, ALWAYS dumped her milk down to the last drop, then carefully rinsed any remaining traces down the drain.  Today, she’d apparently forgotten.

Not entirely sure what he was doing, Kyle looked over his shoulder to make sure he wasn’t being observed.  Fully aware of how wrong this was, yet somehow unable to help himself, he tilted his head back and emptied the contents of the bottle into his mouth.  The milk was sweet, warmer than room temperature, and astonishingly delicious.  The flavor seemed to be almost the distilled essence of Monica’s strange, erotic scent.  Suddenly his head was spinning, his pulse racing.  His groin began to tingle.  In seconds he was hard as a rock.

Kyle let the bottle fall into the sink with a clatter and dashed up to his room, his hard-on bouncing ahead of him as he took the stairs two at a time.  He locked the  door behind him.  It took no time at all to undress, and if this was because his clothes were just the tiniest bit loose on him, he was in no state to notice.  The moan that escaped his lips as he first ran his thumb along the length of his shaft was ear-splitting.  Dimly hoping Monica hadn’t heard, he lay back, holding a pillow over his face, and began to stroke himself.

The pleasure was immediate, sharp, explosive – unlike anything he had ever experienced before.  Kyle thrashed around on his bed, and in only seconds found himself cumming harder than he had in his entire life.  He lay panting for nearly a minute, trying to get his bearings, and faster than seemed possible found himself hard again. 

He pleasured himself this way for over an hour, and completely lost track of the number of times he orgasmed.  When his sister’s image floated into his mind, he didn’t try to push her away.  He let her wander freely through his imagination, and with each release she came to him with a fresh fantasy.  Monica in new places, in new positions…letting him do new things to her…doing new things to him.  And each time, his image of her seemed to be growing bigger, curvier, sexier.  By the end she all but dwarfed him, her head stretching to the ceiling as she sat on the floor, using only her smallest finger to bring him to his end.

It took him a long time to clean up the mess.  He dressed in a baggy set of pajamas, and sheepishly made his way downstairs. 

“Everything alright, lil’ bro?” Monica called from the living room, where she still sat with her nose buried in a book.

“Everything’s great!” he called back, with a bit too much enthusiasm.  “Why wouldn’t it be great?” 

She didn’t answer.  But around the edge of the book, he could see her lip turn up in a smile.  The dish washer was running.  The milking bottle was nowhere to be found.