No sexual thoughts or activity of minors are suggested in the story.
..............................................................................
My 2 parents are physicians. Mom is a pediatrician, and Dad is an attending in the emergency room in a downtown hospital. Both are workaholics and spend long hours at work. Neither one arrives home earlier than 6 pm, and frequently, they are on call too.
As a result, growing up, I could not rely on them for many of my needs. Luckily, my sister, Monica, who's 10 years older than me, helped a lot: Making sandwiches, ensuring I arrived safely from school, and doing homework. Later, she represented my parents in parent-teacher conferences and drove me to after-school activities like swimming lessons and baseball team training.
Only later, in high school, I learned to appreciate the sacrifices she made to help me in my younger years. She was like my real mother. I addressed my parents as Mom and Dad, but in my heart, I thought of them as aunt and uncle who supply the money needed to live comfortably.
I loved Monica and often wondered how she tolerated a brat like me. She was always smiley, patient, and ready to help. I still remember when I got into a fight with another guy in my class. I can't recall the reason, but we both suffered multiple bruises, and then we made peace. The other guy was scared to show up at his house with a bloody nose and torn clothes, so I brought him home. My sister washed our wounds, covered the bloody areas with dressings, sewed the clothes, and then accompanied the guy home to calm his parents. She was a true angel!
Monica got married when I was a senior in high school. At the wedding, I kissed her cheek and joked, "You betrayed me with Larry; I'll never forgive you."
She grinned, "Soul dear, I love you and always will, but it's time for you to leave the nest." The new couple moved to Florida, where Larry's company headquarters was located. The following year, I got accepted to the University of Wisconsin in Madison.
I liked college life from day one. Sometimes, I had to study hard, including evenings and even part of the night. But the mostly-nice group of students and frequent partying on weekends, more than made up for that. By the end of my first year my GPA was 3.9 - Not bad!
...
In the middle of my second year, I heard good news: Monica became pregnant. I called her, "Hey, sis, I am not old enough to be an uncle."
Her familiar laugh sounded pleasant, "Hi, baby, how are you doing at school?"
"Without your help, I am getting lost. Leave your husband, have an abortion, and come help me."
Monica giggled, "Honey, it's time to grow up. Another baby is coming to the world soon."
"But I miss you!"
"You are always welcome here."
"I can't right now. I'll do it during our vacation."
"Good. My due date is late June, so you can help me."
"Monica, take care. I'll be there after my nephew is born."
"Sorry brother, but no nephew. The first one will be your niece."
"I hope Larry is OK with having a daughter. Hugs and kisses."
...
I ended my second year with straight As. My parents took a rare day off to celebrate with me. My dad declared, "I always knew you had it in you. So, what specialty in medicine do you plan to go to?"
"None. I want to become a veterinarian."
Both were surprised, and Mom asked, "Why?"
"Because I like animals, especially large ones, like horses and cows. I think I can do a good job."
Dad said, "Of course you can, but why not humans?"
"Because people may be annoying, noncompliant, and even jerks. Animals are simpler, and I do not foresee any conflict with my animal-patients."
"Well, you have 2 more years to decide. It will be interesting to see if you change your mind."
...
Our summer vacation started, and I spent the first 3 days catching up on my lack of good sleep. My original plan was to enjoy the next few days, meet old friends, and relax. However, everything changed. My sister delivered her baby on my first day off. Unfortunately, Larry, who knew the baby was supposed to be born 2-3 weeks later, agreed to go on a 2 weeks assignment to California to manage an emergency situation in their most important subsidiary.
Three days later, I got a text from Monica, "Soul, no rush, but if you are already on vacation and can help, it would be fantastic."
The next day, I flew to Miami. Nobody was in their house in the suburbs. I ate a pizza at the nearby Domino's and went to sleep, knowing Monica and the baby were ready to leave the hospital the next morning.
I drove her car and brought them to their small house. I had no idea what to do and how to help. While she held the tiny baby, I carried Monica's stuff to the house. The house was prepared for the arrival of the new heir. Monica left the sleeping baby in the new bed and stared at me, "Soul, you grew nicely. I am happy to see you. No kisses yet. I need an urgent shower."
She exited half an hour later, smiling with pinkish cheeks, "Home shower is the best. Did Tiffany cry?"
"No. The little angel is asleep. Let me look at you." She wore a long robe that covered much of her figure. Compared to the way I remembered, the tummy showed a small bulge, and her chest seemed larger than before.
She noticed my eyes and chuckled, "During the pregnancy, my breasts grew. Now, they started filling with milk and continued to swell. From C-cup before the pregnancy, it went up to DD now. I look like a cow."
I smiled, "I like cows. I even told Mom and Dad I wanted to become a large-animal veterinarian."
"Honey, it's nice that you already know what you want. And being selfish, I am happy to hear it because I feel awful being so big."
"Monica, do you want something to drink? Shall I make you a sandwich or bring something from a nearby restaurant?"
"A cup of tea with cookies be nice. You can find everything on the shelf and in the second drawer."
As I was boiling the tea, Tiffany began crying. Monica grinned, "My baby needs to eat too. Pour me the tea and bring it to the living room. We can talk as I nurse her."
Seven minutes later, I was carrying the tray to the table and saw Monica opening her robe, exposing her left boob, and letting the baby milk her.
I stopped in my tracks. Her tit was huge, firm, and looked amazing. The large areola and nipple were beautiful, too. My penis began stiffening...
I felt shame; the simple natural act of breastfeeding my new niece caused me to harden. What a pervert. Luckily, Monica focused on her baby and didn't notice my reaction. After a couple of minutes, she gazed at me, "Isn't she pretty?"
I sat down, put one leg over the other to hide my erection, and blurted, "She is very pretty, almost like her mother."
Monica smiled, "You are sweet, but we both know it's not true. Some cows look good, but not this one. I hope to lose the extra weight in several weeks."
I mumbled, "Please, don't lose too much. I think you look awesome now..."
She stared at me, "Do you wish for me to look like your future patients, or you refer to my bosom?"
I glanced at her and hesitated, "Will I get into trouble if I tell you the truth?"
"Dear Soul, are you afraid of me? Since when we can't say everything we feel to each other?"
"Don't complain I didn't warn you. I think your tits are terrific..."
She giggled, "My breasts are just massive. Too much fat and too much milk, but thank you."