Eventually, the scientist came back with Lenny's chart. "Ok, looking at this, it seems Lenny's bones have adjusted nicely to his new form. There shouldn't be any concerns for them," he said.
"But what about my heart?" asked Lenny.
"Well, it certainly shows signs of improvement," said the scientist, "You should be experiencing less heart palpitations as you are. However, we're a little bit concerned that your cardiovascular muscles have not expanded quite enough. I'm not saying your heart could stop at any minute, but there is a small chance that you might exhibit more heart problems later."
"So what's the prognosis?" asked Lenny.
The scientist pursed his lips before saying, "My best bet is that you could live several months without any heart murmurs or other complications, but you might not be able to do any extra physical activity without having chest pains. It's not a life-threatening situation, but I'd err on the side of caution and proceed with a second dose."
Before Lenny could even reply, Milly said, "That's just fine, doctor. Would you mind leaving us alone now?" The scientist nodded before leaving the room and closing the door behind him. Milly headed over and made sure the door was locked. "Good, now that we have some privacy..." she said.
"I'm guessing you don't want to stick another patch on me," said Lenny.
Milly gave him a mischievous grin and said, "You're getting your second dose in the funnest way possible." With that, she pulled off her shirt. Lenny's eyes widened. Her bra did little to hide the size of her breasts. They had to be at least C cups if not D cups. Milly noticed Lenny's look and grinned widely. "Pretty impressive for a mouse, eh?" she said, hefting up her girls.
"Pretty impressive for a 3-year old," said Lenny. But that comment had a sobering effect on him. The mouse woman who was currently pulling off her pants (wow, that ass looked great) was really just a kid, a toddler in fact. "Milly, I'm not sure we should do this," said Lenny.
Milly paused and said, "I told you that legally I'm considered an adult. And I don't just have the body of a woman. I already know how to drive, how to cook and look after myself. I know exactly what I'm proposing and what that could lead up to. I actually work for a living, posing in outfits that I know will excite lust in men. As I've said before, there are Animalians who are chronologically younger than me who were fully grown before they got a second dose. Really, the only physical difference between me and an uplifted mouse is that I have hair. And more importantly, I'm not just offering because I want to have sex. You're a gentle soul, Lenny, a giant who could have chosen any large mighty animal to splice with but chose one of the humblest creatures. That alone tells me you're a good man. I'm not insisting we should become official mates, but could you consider me your first option?"
As Lenny looked at Milly in her underwear, he saw less of a girl that he might get in legal and moral trouble with and more of a beautiful young woman. So what if her true age was far below the legal limit? Animalia practically had its own set of laws. Normality was completely relative here. And the look in her eyes told her she was sincere. How could he keep saying no? Quite soon, he was holding Milly close to him. He had to lean down quite a bit in order to make lip contact with her, but she didn't open her mouth just yet. Milly moaned slightly as she felt her breasts push against Lenny's large chest. As he reached around her to unclasp her bra, memories of her second dosing came floating into vivid memory...
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"Mama, tirsy," said the tiny young Milly. Being three years old, she was still learning how to speak. Thankfully, her becoming a mouse didn't make her any harder to understand.
"Just a minute, sweetie," said her mother, Myrtle. She was busy unpacking groceries. A lot has changed because of their transformation. For starters, their diets no longer included any meats. Unlike rats, mice were completely vegetarian. And despite its very heavy association in cartoons and stories, cheese no longer had any appeal for them. The smell and taste was too rich for their new palates. Peanuts and peanut butter was now the new snacks of choice for them. But Myrtle didn't mind that much since their diet was a lot less fattening. If only it didn't take Mickey nipping them to make them shift to a healthier diet.
"Mama, tirsy," insisted Milly, tugging on her mom's pant leg.
"Alright, alright," said Myrtle, "What would you like to drink?"
"Mik," said Milly promptly.
Myrtle nodded and got a glass out. The jug of milk she had was fresh from the Brown farm. That place was certainly changing a lot, what with all the animals now building their own houses. But the cows were still producing milk, even if the milk was coming from a higher place than before. But since they were already mice, the milk should be safe to drink. "Here you go, Milly. Don't spill," said Myrtle, handing her daughter her drink.
"Tank you, Mama," said Milly before going to her room. She wished she had some chocolate chip cookies to go along with this, but Mama said something about them 'not being good for her now'. But she promised to make oatmeal raisin cookies, which sounded good enough to Milly. But right now, she was content to play with her dolls and drink her milk.
But not long after she started to drink her milk, Milly started to feel funny. She felt like something was rubbing her all over. It didn't take long for her to notice her shirt was barely covering her belly. She stood up and noticed that everything in the room was shorter than it was before. "Am I getting bigger?" she asked, her diction more coherent than it was before. She walked over to her closet door that had a mirror and several stickers on it. Staring back at her was a mouse girl, but one that had to be 7 years old by that point. "I am! I'm a big girl now!" she said excitedly. She wasn't sure how to explain it, but it was clear that she was getting older.
Her excitement was then replaced by discomfort. Her clothes that she was wearing was getting much too tight now. Her shirt was leaving all of her stomach exposed and her pants were now looking like short shorts. She was suddenly very grateful that she wasn't wearing her overalls today. "Too...tight..." she said through gritted teeth as she tried to pull her shirt off. It was starting to make it hard for her to breathe. Fortunately, with her age came also strength. Her arms soon grew more than strong enough to tear off her straining shirt. Her pants were a different matter. They were really cutting into her waist by this point and even the broken button and zipper did nothing to relieve the pressure. Thankfully, her shorts soon split down the middle, the inner seams of her pants also tearing apart. Milly quickly tore off her ruined pants with a loud gasp of relief. Her training pants fell to the floor, having already snapped open.
Milly looked at herself in the mirror, now looking 11 years old. "I wonder how much bigger I'm gonna get," she said to herself. She noticed her voice was not nearly as high-pitched as it was before. That actually made her feel better. Her old voice was too babyish. Looking around her room, she could see that a lot of stuff was too babyish for her now. For instance, she would definitely not be able to sleep on her little bed now. She wasn't even sure if it could hold her weight. And the dolls she had been playing with before were definitely too simple for her developing tastes. She was going to have to talk to her parents about redoing her room.
But then a slight quiver in her body got Milly's attention focused on the mirror again. She was looking a lot less like a child now. If Milly had to guess, she looked 13 years old if not 14 yet. She was also noticing her nipples were poking out more than usual and the area around them looked puffy. "What is this?" Milly asked as she felt her chest. She gasped as she felt unexpected pleasure. And also unexpected pressure as she could feel her chest growing into her hands. Looking at her reflection again, she saw that her hips were also starting to get wider as her muscles started to make themselves more apparent.
Milly wasn't even confused for a second when the answer just popped into her head. She wasn't sure how she knew, but she knew she was staring puberty. Which means her body was going through the process through which she changed from girl to woman. And she was aware that her chest was growing breasts. She squeezed her breasts again and gave a lower moan. Her growing legs felt a little weak so she lied down on the floor. Her bed would definitely not hold her now. But she was a bit too concerned with herself right now. She could feel her butt growing larger as it took up more area on the floor. Her hips were getting wider to accommodate that. Looking at her arms, Milly could see muscles becoming defined, but not too large. Her breasts were quickly leaving their cone stage and becoming rounder. She tweaked her nipples, reveling in the pleasurable sensation.
Eventually, her crotch started to tingle. Milly looked down between her legs, noticing how the fur there was starting to become damp. She was now quite aware that her little slit was for more than just peeing. Her vagina looked fully-developed, readying to permit a penis inside it and put life-bearing semen into her womb. But since there were no penises available, Milly would have to make due with her fingers. She rubbed her longer, daintier fingers against her lower lips, getting them lubed with her juices. Then she pushed them inside herself. Milly let out a louder moan at that, definitely not that of a little girl but that of a woman. She was soon fingering herself into a frenzy, her other hand clutched tightly around her large breasts, squeezing a little milk from the nipple. She wasn't even bothering to keep her noises down, her gasping growing higher in pitch though sounding no less mature. Before long, Milly out an orgasmic cry as her vagina gushed more juices against her fingers.
As she started to calm down, Milly was processing what had happened to her. She was still a mouse, but now instead of being a mouse girl, she was a mouse woman. She got up and looked in the mirror to be certain. There was no denying that. Her body was fully adult with large breasts, a tight waist, wide child-bearing hips, and a plump bottom that looked rather sexy under her tail. She was probably as full-figured as her mother now. And it wasn't just her body that changed. Her thoughts were a lot maturer, though her knowledge was a bit limited. But she knew enough, she knew she had just masturbated to relieve sexual tension and that her libido was still rather high. Most likely higher than a normal woman since mice were such prolific breeders.
Her thoughts were momentarily interrupted when the door to her room opened and Myrtle walked in, She had obviously heard the noises in her room and wondered what was going on. She was rather surprised to see a naked mouse woman in her daughter's room. She would have been furious about the intruder, especially since her vagina was still glistening from her self-stimulation, but Myrtle could recognize the mouse woman's chestnut hair and her facial features even if they were more adult. Milly confirmed her suspicions when she said, "Hello, Mother."
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A jolt of pleasure shocked Milly back into the present. While her memories of her first orgasm were strong, the pleasure she was feeling now was even better. She was naked on her back again, but this time she was on the examination table. And instead of her fingers, it was a large mouse dick that was pounding into her pussy. Lenny was being gentle, declining to lie atop her and servicing her in the missionary position instead. He was already showing greater mass. Before, he was on the lean side, his body not getting enough protean to build up enough muscles. but now his muscles were finally matching his height. His shoulders broaden to accommodate larger pectorals and back muscles. The abdominal muscles were very detailed beneath his fur. His arms were now very thick, each one being more than the width of both of Milly's arms put together. His legs were now proper pillars to support him. And while Milly couldn't verify how big it was before, Lenny's dick was more than enough to fill her up.
Bringing up memories of her change to adulthood brought Milly all the closer to her peak. It took only a few more thrusts from Lenny to make her let out a squeal as she clenched. That put Lenny over the edge as she started firing deep into Milly. His balls were notably larger than before, no doubt because of being a mouse, so there was quite a large load to be emptied. That huge payload was enough to extend Milly's orgasm even further, if not cause a second one.
It took quite a lot of gasping before either of them was able to speak. Eventually, Lenny gasped, "Was I good for your first?"
"Definitely so," said Milly. She partially wondered why she held back against having sex with anyone. Even Mickey wasn't a consideration for her, her former pet being too much like a brother to her. But she was glad to have saved herself for this giant mouse.
"You were my first too," said Lenny.
Milly gave him a surprised look. "I would have thought you would have had more experience," she said.
"Actually, most women find my tall stature off-putting," said Lenny.
Milly smiled as she sat up. "Their loss," she said in a husky voice. Lenny leaned down to kiss her. Milly allowed her hands to travel his broader chest as they made out. She particularly paid attention to his large pecs and the strong heartbeat she could feel under them.