After the intense night of fun with Gleaming Shield, Bolero returned home quite exhausted, finding himself in bed only a few minutes after arriving. Sighing contently, he stared up at the ceiling as he recalled the events of the night, unable to get Gleaming Shield's breast-growth spell off of his mind. "Mm...tomorrow is gonna be so slow." he chuckled softly to himself as he closed his eyes to go to sleep, already eager for the next time that he would be alone with his lovely marefriend.

Quickly drifting off to sleep, the stallion prince went on to inevitably dream about his fun experience with Gleaming Shield and her massive chest, which only helped to fuel his arousal when morning came. Finally being roused from his sleep a while after sunrise, Bolero yawned and blinked his eyes a few times, feeling quite rested from the peaceful sleep, but upon moving his legs a bit, he immediately took notice of the raging erection between his legs.

"Heheh...someone's up early." the prince grinned down at the tent in the blanket; all of the sexy dreams having caused quite a potent morning wood for him. Sitting up and pushing the comforter aside, he began to idly stroke that huge tent in his boxers, feeling it throb in arousal. "Let's take care of you then, shall we?" he thought out loud as he stood up, glancing over towards the small bathroom at the other side of his room.

Bolero proceeded to take a shower as he did every morning, helping him wake up a bit more as he cleaned his coat and mane; the steamy temperature of the water only keeping him aroused; his member twitching eagerly as it stood up between his legs. Finally done cleaning himself, the stallion then reached down and grasped his eager shaft, beginning to steadily stroke it up and down while thoughts of Gleaming Shield's inflated chest filled his mind.

"So big and soft...mm..." he sighed happily as he recalled the wonderful feeling of the milky melons squeezing around his shaft, thrusting firmly between them while small amounts of milk oozed from the two perky nipples. His thick shaft only throbbed harder in response to all of the naughty thoughts, releasing drop after drop of precum as the stallion's orgasm built up rather quickly.

While he was absorbed in his masturbation though, he didn't notice the bathroom door slowly creak open, not being able to see it very clearly either, because of the translucent glass of the shower door. As he happily jerked himself, the very mare he was fantasizing about slowly approached the shower, wearing only a pair of lacy panties and a pink tank-top. It wasn't until she walked right up to the shower and pressed against it that Bolero finally noticed, gasping in surprise and pressing back against the wall of the shower.

"Ngh! Gleaming Shield? What are you doing here?" he gasped, the shock of surprise disorienting him a bit, causing him to slip and fall back on his butt against the corner of the shower. Despite his surprise though, he noticed two obscenely-large orbs below her face; the mare's chest was very clearly larger than its normal size.

"Mm...I thought you could use a hand with that, my love." the mare replied in a sultry tone, sliding one hand down and pulling the shower door open, giving Bolero a clearer view of her now, her chest unmistakably swollen back up to the same massive size as last night; barely contained by the pink tank-top. As she stepped into the shower the fabric became soaking wet, only making it cling to her huge curves; the prince's member throbbing eagerly to the sight of Gleaming Shield's bust; her large, perky nipples clearly visible now that her top had become soaked.

"Ahh...I s-suppose...don't scare me like that, though!" Bolero groaned lightly in annoyance, a bit confused as to why the mare had come to Canterlot Castle so early in the morning, grunting a bit as he tried to stand, but the pain in his lower back caused him to cringe a bit.

“Oh, did my sweet prince hurt himself?” Gleaming Shield giggled softly, kneeling down in front of the prince and grasping his member, beginning to slowly stroke it up and down. “Don’t worry, I’ll make it all better.” she teased with a grin, kissing the head of the prince’s scepter.

"Mmnh, what a coincidence...will you show up here every time I think of you?" he grinned playfully at the busty unicorn, panting a bit from the pleasure of that soft hand stroking up and down his length.

"If that's what makes you happy, dear." Gleaming Shield smirked back and leaned in closer, nuzzling at Bolero's snout as she jerked his length a little faster, squeezing it with her soft hand. "I love you, my prince." she added, leaning up and pressing her lips against Bolero's, closing her eyes as she kissed him deeply, continuing to swiftly jerk his twitching member.

"Mmnh...!" The lustful prince moaned in pleasure and returned the kiss, opening his lips a bit and sliding his tongue out to meet the mare's, french-kissing her while he enjoyed the pleasure of her stroking hand, smearing warm precum all over it as his orgasm drew closer and closer. As Gleaming Shield cuddled in closer with him, he felt her soft chest squish against him, only serving to arouse him even more; his own hands coming up and gently squeezing the hefty melons, loving the feel of their softness in his hands.

The passionate kiss between the two lasted a few brief moments before Gleaming Shield slowly withdrew, feeling that the stallion was about to cum, from the powerful throbbing his member was doing. Licking her lips, she smirked lustfully at Bolero before leaning down, her hand sliding down to the base of his shaft as she opened her mouth and quickly engulfed at least six inches of the throbbing royal scepter, beginning to eagerly suckle on it.

"Ahh...oh, yes...Gleaming!" Bolero moaned in bliss from the surge of pleasure that the mare's tongue and lips provided, closing his eyes tightly while his member only throbbed harder in her mouth, gushing off loads of precum as it was about to erupt any minute now. His hips instinctively bucked upward a bit against the mare's steadily-bobbing head, while he gently grasped her horn with one hand, lightly squeezing and stroking it in return. "Gonna...nnh, cum...!"

Gleaming Shield sighed and panted lightly through her nostrils as she kept bobbing her head, enjoying the gentle pleasure emanating from her horn while eagerly awaiting the prince's orgasm; her tongue swirled around the tip of his member and slurped up every glob of pre, while her lips massaged the shaft, sliding up and down with her head-bobbing. Wanting to bring the prince to a powerful orgasm though, her hands came up and pulled the wet tank-top down, exposing her massive melons, before she pushed her chest forward and squished them around the lower half of his member, squeezing them nice and tight as she kept suckling, pushing Bolero's pleasure to new heights.

"Nngh...oh, good Solaris!" the alicorn prince cried out loudly in pleasure as he felt the soft breasts completely encase the lower half of his twitching scepter, easily pushing him over the edge of his orgasm. "I'm cumming..ahh...babe...!" he groaned as his eyes closed tightly, bucking his hips up against the mare even more as he felt his member throb even harder, releasing a powerful stream of his royal semen into Gleaming Shield's mouth and throat.

Keeping her soft chest squished around the throbbing stallionhood, Gleaming Shield eagerly gulped down every last drop of seed that gushed into her mouth, firmly dragging her tongue along the underside of the shaft to tease the prince with even more pleasure; wanting to milk out as much of his seed as she could. After a good deal of gushing and gulping, Bolero's orgasm finally died down, leaving him panting blissfully as Gleaming Shield finally pulled her head back, licking her lips gently.

"Ahh, oh man...that was great, Gleaming Shield..." Bolero spoke between his exhausted panting, the huge combined pleasure of the blowjob and titfuck having easily overwhelmed his body. Still leaning back against the shower wall with his eyes closed, resting his hands on the edges of the shower while his member throbbed lightly in his afterglow. "I just love that breast growth spell of yours..heheh..."

"Mm, and I enjoyed your love, my dear...it's so delicious." Gleaming Shield replied with a smirk, though her voice sounded noticeably deeper, causing the prince to blink his eyes open in confusion; quickly glancing down at the mare and only widening his eyes more as he no longer saw a mare in front of him, but instead a male Changeling, its smooth hand stroking up and down Bolero's length while its long tongue flicked out and slurped the tip of it. The changeling was only halfway through its transformation though; its upper body muscular and masculine, while the lower half was still Gleaming Shield's waist and legs. "And this handsome cock of yours...mm...so thick and juicy!"

"What the...?!" Bolero gasped, not only surprised at the fact that the busty mare was actually a changeling, but at the fact that a male changeling had just fellated him. "Who are you...? And what have you done with Gleaming Shield??" he growled, trying to raise his hands, but found that they wouldn't budge. Glancing between his hands, he gasped as he saw both of them were being held against the wall with some kind of sticky green goop, which was slowly spreading up his arms as well.

"I haven't done anything with her, my sweet. I was never a big fan of mares." The changeling explained with a chuckle as he stood up and turned the shower off with his magic, licking his lips again as he glanced down at the hunky alicorn prince. "Stallions' love is much more delicious, and a so much more fun to extract." he smirked lustfully while his transformation finally completed, leaving him in his full Changeling form, all except for his crotch, still covered by the panties.

Prince Bolero only blushed in embarrassment as the studly Changeling stood before him, still uneasy from knowing that a male had sucked him off and kissed him passionately. His attention was drawn towards the Changeling's panties though as he noticed them bulge, the female sexual organs finally transforming back to male ones; Bolero's blush only deepening as he watched that bulge grow and grow, the clitoris extending and taking the shape of a stallionhood as it rapidly grew and hardened, pushing up and out of the changeling's panties.

"Mmnh, much better..." it spoke in a sultry tone, reaching down and grasping the twitching 16-inch erection between its legs, stroking it slowly while two more bulges appeared in the panties, clearly round-shaped and hanging a bit low in the garment. "Oh, how rude of me, darling...I forgot to introduce myself, heh...got a little carried away gazing at your magnificent body." The hunky changeling chuckled and grinned, crossing his arms over his chest now. "I am King Nymphamos, ruler of the Changelings. You should feel honored, having royalty such as myself feeding off of your love."

"Shut your trap, Swiss cheese dick!" Bolero growled, still struggling against the rapidly-spreading goop, but it was covering most of his upper body now, sticking him to the wall of the shower as it began to spread down his body. "You're not the only royalty here! And you're going to get a royal ass-kicking when my friends find out that I'm missing!" he threatened, forgetting a crucial detail about the Changeling king for the moment.

King Nymphamos only cackled in reply, shaking his head a bit. "Silly prince. Your friends will not discover that you're missing, because I'm going to take your place and completely drain them of their love." he smirked and licked his lips again, figuring that if the stallion's love was this potent, then surely Gleaming Shield's would be just as bountiful. "It has been too long since I've been able to feast on so much raw passion."

"Bastard...!" the alicorn prince grunted as he struggled a bit more, but his movements became more and more futile as the green goop spread across almost all of his body now, pinning his legs to the floor as well, before beginning to slowly creep up his neck. His horn was glowing as well, desperately trying to work some kind of magic on the sticky substance, but magic seemed to have no visible effect on it.

"Hehehe...now you stay put, my delicious stud. I've got some love to feed on." Nymphamos smirked playfully as he leaned down and grasped the stallion's chin, pressing his lips up against Bolero's and kissing him deeply, much to the stallion's disgust. As he pulled away, the green ooze covered the stallion's snout, now completely encasing his body, keeping him trapped in the shower. "Don’t play with yourself while I’m away, studmuffin. I want your love reserves to be building in anticipation of my return.”

Prince Bolero could only watch helplessly as the changeling king's body shapeshifted again, this time quickly matching his own body, looking like a perfect clone of the alicorn prince, with the exception of his eyes, which had a green tint to them. "See you later, my handsome prince." Nymphamos blew a kiss to the trapped alicorn before closing the shower door and leaving, heading off to assume the prince's identity.

--------------------------

Several hours later, Dusk Shine was just returning home after his daily lessons with Lord Solaris, having been a bit distracted during the day from constantly thinking about what he had seen of his sister and Bolero the previous night. Entering the house, it was quiet as usual with his parents still being at work, all except for the faint sound of movement and metal clanking coming from the basement; the colt recognizing the sounds as Gleaming Shield's weight lifting machine.

After setting his bag down beside the front door, he approached the staircase to the basement and quietly tiptoed down each step as to not make any noise; suddenly stopping as he heard the metal clanking come to a stop, followed by a few footsteps, fearing that his sister was coming back upstairs. A brief moment later though, he heard her hands slap against something metallic, before hearing light grunts and panting.

The colt continued down the steps and approached the door to the weight room, peeking around the corner of the open door and seeing his sister doing pull-ups, wearing nothing but a yellow tank-top and a pair of black nylon shorts. She was a good ways into her workout however, leaving her body saturated in sweat, which soaked into her shirt and made it cling to her body, accentuating every curve on her torso, including the two soft mounds on her chest.

Blushing lightly again, Dusk Shine continued to watch his sister pull herself up and down on the bar, the sight of her chest through her shirt only causing his head to fill with thoughts of his sister's chest swelling up massively like it had done last night. After only a minute of watching, he gulped softly as he felt his pants becoming tighter already with his quickly-stiffening member, making a noticeable bulge over his crotch. "Mnh...I wish she would make them big again..." he sighed quietly as he kept watching the slim unicorn work out, rubbing at the bulge in his pants as it grew harder and harder with each passing moment.

Despite his ever-increasing lust, the young colt couldn't help but feel slightly confused as to why he was finding his sister so attractive all of a sudden, having never really thought about her chest in this way until he saw it grow so huge. His hand slipped into his pants now and began to stroke his eager erection through the fabric of his underwear, a few quiet groans of pleasure escaping his lips while he kept his eyes focused on Gleaming Shield's chest.

It wasn't until a couple minutes later that the unicorn mare finally caught a glimpse of purple out of the corner of her eye, letting herself down from the bar and turning towards the door, only to see the bit of purple suddenly disappear, followed by quick footsteps down the hall and up the stairs. Of course, she knew when the colt got out of classes, so she knew it was him, but she wasn't exactly expecting him to be spying on her again so soon.

"What's gotten into that colt?" Gleaming Shield thought out loud, wiping her brow gently before turning and glancing at her reflection in the wall-mirror, noticing that the sheer amount of sweat that she was putting out had caused her shirt to cling tightly to her body, making the two C-cup mounds on her chest rather obvious. "Ugh...that's probably why." she giggled softly before tugging her shirt, loosening it from her body.

"Mom and dad won't be home for a while, though...I guess I could go and give him a bit of sex ed." she thought, stepping out of the weight room and heading back upstairs, seeing the colt's backpack at the front door as she passed it. "Hey, Dusk!" she called out towards the staircase to the bedrooms, though she didn't get any response. Slowly and quietly ascending the stairs, she listened for any sign of the colt, only hearing silence as she reached the top, glancing down the hall at Dusk Shine's room.

As she arrived at the door, she gently placed her ear against it, finally hearing something: The creaking of bedsprings coming from inside the room. They were much too soft to be caused by the colt jumping on his bed, and they were also quite rhythmic, making a steady pace of soft squeaking. Gleaming Shield grinned a bit, somewhat amused by the fact that she was listening to her younger brother masturbate, to what she assumed were thoughts of her own chest.

Grasping the doorknob, she quickly turned it and pushed the door open, causing Dusk Shine to gasp in surprise and jump a bit, scrambling to cover up his erection with the blankets on his bed. "G-Get out of here, Sis!" he groaned, panting a bit from the shock as he held the covers up against his body, though Gleaming Shield had already seen what he was hiding. "Didn't anyone ever teach you to knock?!"

Gleaming Shield only closed the door behind her as she stepped further into the room, crossing her arms over her chest and glaring lightly at the stallion, who was still panting a bit from the surprise intrusion. "That's the second time now that I've caught you spying on me, Dusk." she stepped a bit closer to him as he blushed deeper, still holding the blanket up to hide his stallionhood.

"I'm sorry, sis...I don't know what's wrong with me!" Dusk Shine glanced down at the raging erection between his legs, throbbing eagerly from being jerked just moments ago. "Ever since I saw you and Bolero last night...I can't stop thinking about your boobs." he confessed, still blushing in embarrassment as he looked back up at his sister.

"Hmph, naughty little colt." Gleaming Shield grinned playfully, gently poking the colt's forehead and running her fingers through his mane. "Didn't anyone ever teach you that it's impolite to spy on mares when they're playing with their boyfriends?" she giggled softly, poking her tongue out a bit as she tried to lighten the mood, not wanting to see her brother so distressed.

Dusk Shine sighed in relief, as though the mare's playful grin assured him that she wasn't really that angry, if at all. "I don't know what came over me...I just saw you and Bolero playing like that...and when you made your boobs grow really big, it made me feel really weird." he explained, finally letting the blanket down a bit, but still keeping his crotch covered. "I couldn't stop thinking about it during my lessons today..."

The mare only smiled softly and stroked her hand over Dusk Shine's forehead and down to his neck. "Don't worry about it, Dusk. You're at the age when your body is changing, so I'm not surprised." she assured the colt, looking into his eyes as he glanced up at her. "Heh...so my little brother's got a thing for big tits, too" she giggled mentally, amused at the similarity between her brother and Bolero.

"Yeah...I've been trying to find out more about it, but Solaris said that I shouldn't read books about these kinds of things until he thinks I'm ready to learn about them." Dusk explained, blushing lightly again. "So I've only been able to experiment with it by myself..." he glanced down between his legs again, feeling his stiff member starting to soften up again from the lack of attention.

"He doesn't want you to learn, huh? What a jerk." Gleaming Shield giggled again, grinning down at her brother. "Don't worry, Dusk Shine, I'll teach you everything you want to know. Seeing as you're so eager to learn, I think it's high time you studied a little sex ed." she explained as she gently grasped the covers and pulled them down, gazing at the semi-hard erection between his legs.

Dusk Shine only continued to blush as his sister leaned forward a bit ogled his package, his own gaze met with the cleavage of her soft chest, mostly covered by her bra though. "Uhm...I have been wondering...is it supposed to feel good when I rub it?" he glanced up at his sister's face again, remembering last night when he had masturbated. "Because I've rubbed it a few times now, and each time it really good...or is that bad?"

"Hehe, no, silly. It's supposed to feel really good." Gleaming Shield poked her tongue out a bit as she looked back up again, noticing the colt staring at her chest. "When you see something you find attractive, your penis will get really hard like that, signaling that you're ready for the kind of playing you saw me and Bolero doing." she explained, trying not to blush herself. "Mares' chests are naturally attractive to stallions, which is why you can't get them out of your thoughts." she giggled softly, gently shaking her chest back and forth, making the soft mounds jiggle behind her bra.

"Oh...I guess that makes sense, then..." Dusk Shine nodded softly, gazing at his sister's chest again as it jiggled, only sending a surge of arousal through his body; his member slowly beginning to stiffen up again. "How did you make them bigger, though? I've never seen a mare do that."

"Just a little spell I learned for Bolero." The unicorn mare answered, looking down at her chest as well, gently rubbing a hand it through her yellow shirt. "Like a lot of stallions, he finds large breasts very attractive...mine aren't that big, though." she poked her tongue out playfully again, grinning a bit. "I guess you really like them too, if you couldn't get them out of your thoughts."

"Y-Yeah...my body felt really weird when I saw them grow really big." Dusk Shine gulped softly as he remembered the feeling of arousal that quickly grew within him upon seeing his sister’s chest grow so massive. "Do you...uh, can you make them grow big like that, again? I won't touch them or anything...I just want to see."

Gleaming Shield blinked a bit, not expecting such a request from her brother, but thinking about it for a moment, she realized it would be perfect “visual aid” to help her with this “lesson”.

"If you really want me to, Dusk. I suppose I kind of owe you now that I've seen you naked." she giggled softly as she grasped her shirt and pulled it up over her head, revealing her chest to the colt, still covered by her bra of course. Blushing lightly, Dusk Shine watched as his sister then unclipped her bra and slid it off, revealing her soft C-cups. Already, his member had stiffened back up to its full hardness, lightly throbbing between his legs.

"Ready? Here goes." The older mare said, before her horn began to glow with magic, replicating the spell that she had used last night; her own cheeks starting to blush lightly as she felt her chest start swelling again, slowly growing larger and softer before Dusk Shine's eyes. Just as they had done the previous night, the two melons swelled steadily, growing through cup size after cup size, already double their previous size and still growing.

"W-Wow..." Dusk Shine gulped again as his gaze locked onto the two expanding breasts, his blush deepening as his arousal grew, causing his member to twitch and throb harder between his legs, standing straight up now. It was so hard that it hurt. His sister's chest was passing a G-cup now as it kept growing, the two nipples increasing in size as well, to match the ever-increasing size of the huge breasts. "They're getting...so big!" his eyes widened a bit while the familiar feeling of arousal from last night surged through him again, causing his heartbeat to quicken.

"Hehe...someone's really enjoying them, I see." Gleaming Shield giggled softly as she watched her brother staring intently at her huge chest, seeing his erection standing at attention and throbbing eagerly. After a few more moments, her chest ceased its growth, well past any normal cup size and immensely soft, with large, perky nipples as well. "Go ahead, Dusk...give them a little feel, if you want." she blushed and smiled warmly down at the colt, swiveling her upper body left and right, causing the two milky melons to jiggle teasingly.

Biting his lip gently, the colt slowly reached forward and placed both of his hands on his sister's chest, feeling its softness as he stroked over them. "They feel...pretty nice." he marveled at just how soft the two oversized breasts were, only causing the feelings of arousal within him to surge even higher; a bead of pre forming on the tip of his erection as it continued to throb in need.

"Mm, don't they? I love how soft they get, too..." Gleaming Shield sighed softly from the gentle pleasure Dusk Shine's rubbing provided to her chest, while gently stroking her own hand down the colt's side and towards his waist. "Don't be afraid to give them a little squeeze, Dusk." she playfully winked to him, pressing her chest forward a bit against his hands.

Of course, Dusk Shine already thought to squeeze them, but was unsure of whether or not his sister would like it. Hearing her request though, he eagerly squeezed at the soft melons, grasping and groping them over and over again, finding their soft texture quite enjoyable. As he squeezed though, he felt a bit of moisture on his hands, seeming to originate from the mare's large nipples. "Uh...s-sis...I think something is coming out of them..."

The busty unicorn blushed now as well, feeling herself lactating slightly from all of the squeezing and squishing of her soft breasts. "Oh, sorry...mnh...I forgot about that..." she sighed from the soft pleasure, while sliding her hand closer to Dusk Shine's crotch, soon grasping his rock-hard length and squeezing it gently, feeling it throb in her hand.

"Hehe...let your big sister take care of this for you." she grinned playfully, rubbing her thumb over the tip of the colt's shaft and smearing the clear pearl of liquid that had formed there.

Dusk Shine however was fascinated by the liquid slowly escaping the big nipples, staring intently at them as he felt a strange attraction to them; urges to press his lips to the perky nub welling up within him. Leaning forward, he gently grasped the mare's right breast with both of his hands before opening his mouth and latching his lips around the big nipple, starting to slurp at it and gently suck it.

"Ah...what are you...nnh!" Gleaming Shield gasped from the colt's sudden actions, though his suckling only gave her even more pleasure, feeling like a pressure in her chest was being slowly relieved. "Ohh, Dusk...that feels nice..." she moaned as she began to stroke the twitching erection up and down, squeezing it occasionally as her soft hand jerked the length slowly. Small amounts of milk flowed steadily into the colt's mouth as he kept suckling, spreading a delicious, creamy taste over his tongue.

"Mmmpmh..." Dusk Shine groaned in pleasure from the soft hand stroking his stallionhood, closing his eyes while he kept sucking on the big nipple, eager to taste more of the delicious liquid that flowed forth. Despite it being artificial, magically-created milk, it tasted sweeter and creamier than any cow's milk that he had tasted previously, and the warmth of it was helping to soothe his body. At the same time, his own member continued to throb and twitch from the soft stroking of Gleaming Shield's hand, oozing more droplets of his warm precum.

"That's it...mm...enjoy your sister's milk, Dusk..." The busty unicorn sighed happily as she stroked her free hand through the colt's mane, midclosing her eyes from the suckling, feeling more and more of the warm liquid escaping her nipple as the horny colt sucked a little harder. In response, she accelerated her stroking slightly, squeezing her soft hand around his member a little tighter as well, feeling the warm precum smearing over her hand as well, slicking up the twitching shaft as she kept jerking it.

After a couple more minutes of suckling, Dusk Shine finally pulled back from the mare's teat and moaned happily, panting a bit from the ever-increasing pleasure the busty unicorn's soft hand was giving him. "Ohh...mmnh...it tastes so good..." he moaned, blushing deeply as he stared up at his older sister with a lustful look in his eyes, feeling the familiar pressure building up between his legs, his orgasm approaching quickly from the relaxed state that the milk had induced upon him.

"Hehe...good to know." Gleaming Shield smiled warmly down at him, slowing her stroking to a stop and lightly squeezing his shaft, while thumbing over the tip of it. "Ready to move on then, Dusk? I know you'll love what I've got planned." she winked to the blushing colt, lightly jiggling her huge breasts back and forth again.

"S-Sure..." Dusk Shine nodded, feeling another surge of arousal shoot through him as he watched the huge melons jiggle again, only causing his throbbing erection to release another bead of pre against his sister's thumb. Thinking of what the mare had in mind, he remembered when she pressed her breasts around Bolero's cock, making him quite anxious to feel them around his own member. "What are you gonna do, Gleaming?"

"I'm going to let you feel my chest in a much better way." Gleaming Shield smiled and nuzzled the colt's snout affectionately, before kneeling down beside his bed and scooting up closer to him; the lustful colt watching as those two jiggling breasts moved closer and closer to his crotch. "You saw me do this with Bolero, didn't you?" she teased, grinning and slipping her tongue out a bit as she grabbed her swollen orbs and spread them apart a bit, leaning forward before pressing them together around Dusk Shine's cock, completely surrounding it in soft, warm breast, all except for the tip of it.

"Oohh!!" the colt moaned and shuddered from the feeling of the immense softness gently squeezing his member, only making it throb harder, releasing a small shot of precum into his sister's cleavage. "Nnh...th-that feels...so good!" he groaned in pleasure, placing his hands on Gleaming Shield's head while he gazed down at her, seeing his erection squished snugly between the two huge knockers. “It feels even better...nggh...than homework!”

While most mares would consider this an insult, Gleaming Shield knew how seriously her younger sibling took his studies. She knew that being compared to homework was the apex of compliments for Dusk Shine.

"Hehe, I bet it does...Bolero really enjoyed it too." Gleaming Shield giggled softly, enjoying the feel of the rock-hard member twitching between her breasts as well, teasingly squishing them against the shaft a couple times to tease her brother with more pleasure. "Here goes, then." she added, before beginning to slowly move her breasts up and down, rubbing them along the colt's shaft and massaging it nicely.

"Ahh...ohh Gleaming...nnh...!" Dusk Shine groaned and grunted blissfully, the soft breast-massage feeling many times better than the mare's hand, while the somewhat tight squeeze only helped to milk out his precum, smearing between the soft mammaries and soaking into the mare's coat. With all of the wonderful pleasure coursing through his member, the pressure only built up more and more, his orgasm rapidly approaching now as his member throbbed harder between the mare's huge breasts.

Hearing her brother moaning and grunting in pleasure only made Gleaming Shield blush lightly again, happy to know that she was pleasing him so well. She kept up her steady tit-fucking though, feeling the colt's erection throb and twitch more frequently between her milky melons, knowing that he was about to blow any minute now.

"Mm, let’s test your concentration...recite Pi to fifty places." she teased with a playful grin, accelerating her movements a bit while pressing her hands more firmly against the sides of her massive breasts, only squishing them tighter around the colt's shaft.

Always eager share his knowledge, Dusk Shine began reciting the value of pi from memory.
"3.14159 26535," Dusk Shine gasped, breathlessly. It took every ounce of willpower to keep from cumming. Gleaming Shield managed to sync the movements of her breasts to her brother's recitation, starting to alternate between raising and lowering her massive bosoms with each decimal digit.

"89793 23846," Dusk Shield grunted, feeling his balls contract in anticipation of release, "26433 83279 50288." Leaning his head back as he was so close to finishing, he finally groaned out loud from the surge of pleasure the tight squeeze provided, easily pushing him over the edge of his orgasm.

"41971...69...Oohh, Gleaming...nnghh...!!" he cried blissfully as his pleasure peaked, causing his member to throb wildly between the soft mammaries and release sizable gushes of seed, splashing a bit onto the mare's face while most of the goopy carnal fluids landed on her chest and in her cleavage, making a small sticky mess on the mare's coat.

"Ooh, that's it!" Gleaming Shield gasped lightly as she felt the hot liquids splash her, still squeezing her chest nice and tight around the colt's length as his orgasm subsided, a few strands of his seed spread across her cheeks while most of it had splattered all over her chest and oozed down into her cleavage. "Mmnh...how was that, hm?" she grinned up at the panting, slightly-exhausted stallion, still feeling his shaft throbbing lightly between her soft melons.

"Nnh...that was...amazing..." Dusk Shine sighed blissfully, opening his eyes again as he gazed down at his sister, smiling a bit in return as he basked in the afterglow of his powerful orgasm. "I've never felt that good in all my life! That was even better than acing a pop quiz!"

"Glad to hear it, little brother." the busty unicorn smiled and leaned forward a bit more, nuzzling the colt's belly gently. "I guess that concludes today's lesson?" she added with a playful wink, releasing Dusk Shine's member from between her breasts and standing up again, watching the colt as he collapsed back on his bed and sighed happily again, smiling up at her.

“Thanks...mnh...Gleaming Shield.” he panted softly as he caught his breath, his afterglow fading slowly as well. "Isn't Bolero going to be mad at us, though? I thought this kinda thing was only for...you know, coltfriends and marefriends."

"Don't you worry, Dusk. What he doesn't know won't hurt him." Gleaming Shield giggled softly as she leaned down and gently kissed the colt's cheek, rubbing his chest lightly. Neither of them were aware that someone was watching them from outside Dusk Shine's window, however.

"And besides, it's my job as a big sister to make sure my little brother is well-educated about these kinds of things." she smiled warmly as she stood back up again, picking up her bra and shirt from the side of the bed. "I'm gonna go clean myself up now. See you later, Dusk." the busty unicorn added, before turning and leaving the room, heading off to the bathroom to clean up the sticky mess all over her massive melons.

"Mm...how intriguing." came a voice from outside the bedroom's window; King Nymphamos perched on the side of the house, having watched and heard most of what had gone on within the bedroom. "It seems this little colt has much more love for his sister than his sister does for her coltfriend..." he smirked devilishly, though he immediately realized that this would mean disguising as a mare again; his body shuddering lightly at the thought.

"Hmph...it will all be worth it in the end, I suppose." he scowled a bit, before carefully climbing back down the wall and entering the house through a first-floor window. As soon as he heard the water running from the shower, he smirked and shapeshifted, taking on the form of Gleaming Shield once more, complete with oversized chest. Though now that he had knowledge of the colt's desires, he glanced down and placed his hands against the soft mammaries, focusing his magic a bit and swelling them a few cup-sizes bigger.

"Heh...that should be enough." the disguised mare smirked as she lightly fondled the gigantic breasts, almost as big as watermelons now, and incredibly soft as well. With each step she took, the huge melons jiggled slightly, swaying and bouncing against each other as she slowly climbed the staircase, licking her lips gently in anticipation of feeding on the vast amount of love within Solaris' student.

Approaching Dusk Shine's room, she brought her face closer to the nearly-closed door and peeked inside, seeing the colt still sitting on his bed, stroking his semi-hard penis slowly and gazing curiously down at it. "Mm, time for round two..." she grinned as she pressed the door open, surprising the purple unicorn again, though this time his jaw nearly dropped to the floor as he saw the two massive breasts, even bigger than they were just a few minutes ago.

"W-what? Gleaming? I thought you said...wha...you made your chest even bigger?" he blinked in surprise, immediately feeling another wave of arousal as he stared at the two giant knockers on his sister's chest, causing his member to fully harden again, despite still being somewhat fatigued from his previous orgasm.

"Mm, I cleaned up nice and quick, so that we could start our next lesson right away..." Gleaming Shield replied in a sultry tone, midclosing her eyes and grinning lustfully as she slowly approached the colt, swaying her body with each step as to purposefully jiggle her massive chest as much as possible. She walked right up to Dusk Shine and stopped once her over-inflated chest was right in front of his face, smirking down at him and licking her lips gently as she gazed at his throbbing erection. "I made them even bigger, just for you, little brother."

Dusk Shine was speechless. At the previous grown size, he already thought they were gigantic, but here was a pair of breasts that surpassed that size by quite a bit, to the point where he would have started to question their anatomical possibility, if it weren't for the raging erection between his legs steering his thoughts elsewhere. Raising his hands up again, he grasped the two giant jugs and squeezed them, feeling like soft, warm gelatin against his hands, jiggling so perfectly to his every push and press.

"Ooh...you love them, don’t you, little brother?" Gleaming Shield moaned seductively as her chest was lightly rubbed and squeezed, jiggling it even more against the colt's hands, while bringing her own hand down between Dusk Shine's legs and grasping his rock-hard member, teasingly stroking and squeezing it once more. "And you're so hard...mm...let's move on to lesson number two, Dusk Shine." she began to blush lightly to the gentle pleasure, while her horn glowed a faint green color, beginning to slowly absorb the colt's love already.

"Oh...uhm...okay..." Dusk Shine nodded softly, still staring at the two giant breasts though as he lightly pressed his hands against them. "What are we gonna do, sis...?" he asked curiously, finally looking up at her again, just barely seeing a green glow in the mare's eyes, but not thinking much of it; his mind instead focused on what fun he was about to have with his sister.

"I'm going to teach you how to buck a mare, my dear brother." Gleaming Shield grinned lustfully down at the colt, leaning down and kissing his snout gently as she kept lightly stroking his member, only causing him to groan in pleasure; his mind slowly being tainted by the Changeling magic, while more of his love was drained away.

Meanwhile, the real Gleaming Shield sighed happily in the shower, lightly stroking her hands over her smooth melons as the hot water ran over them, washing away her brother’s semen with the help of a bit of shampoo. She was starting to become slightly attached to the swollen mammaries, especially now that her two favorite stallions in the world loved them so much. "Hehe...if only I wasn't joining the Royal Guard." she giggled softly, squishing the two huge breasts together again and sighing happily; her horn glowing again as she shrunk them back down to their normal C-cup size.

After washing herself completely, she turned off the shower and stepped out, levitating a couple large towels with her magic and wrapped them one around her body, before grasping the other and drying her hair off with it. Stepping out of the steamy bathroom, her ears perked up a bit as she heard a creaking coming from upstairs, raising an eyebrow in confusion. "Hm? What is that colt doing up there?" she walked over towards the staircase and began to ascend it, only increasing the clarity and volume of the sounds.

She also noticed a rhythm to them, just like she had heard when she found Dusk Shine masturbating, except they were a bit louder. "Is he masturbating AGAIN? Ugh, that horny little colt will be jizzing dust by morning at the rate he’s going." she giggled softly, walking up the stairs to head to her room, though just as she pushed her door open, her ears twitched and stood up straight again as she heard a feminine moan come from Dusk Shine's room.

"What the..." she thought out loud, her stomach sinking a bit as thoughts rushed through her head as to what the source of the moan was. Rushing down the hall, she grabbed the handle on Dusk Shine's door and quickly shoved his door open, bursting into the room only to see the colt kneeling between the legs of a white-coated mare with impossibly large breasts, thrusting his cock in and out of her pussy. "Dusk! What are you, who is...HUH?"

Dusk Shine gasped in surprise, pulling out of whom he thought was his sister, his eyes widening as he glanced back and forth between the two mares. "What...huh?? Gleaming...? What's going on?" he cried, completely scared and confused as to why there seemed to be two of his sister. Gleaming Shield was equally confused, shaking her head a bit and staring with wide eyes at what appeared to be a perfect clone of herself, but with a much, much larger chest.

“Mmm...your brother’s love is so delicious.” The impostor mare spoke in a seductive tone, smirking and licking her lips gently once more as she turned her gaze to Gleaming Shield, the green glow in her eyes becoming obvious now.

TO BE CONTINUED...