It was a surprise to everyone, but most especially to one Harry Potter, when the headmaster of Hogwarts 'requested' that Harry take care of their de-aged Potions Professor.
There had been an accident just a couple weeks into Harry's sixth year of school. Professor Snape was no longer the Potions Professor, but he had been in the classroom just as the explosion happened. Pained screams and two minutes later found the sixth year potions class with a toddler Severus Snape. Harry, noticing Slughorn's slight inattentiveness and shock, rushed the toddler up to the headmaster's office.
And thus Harry was stuck with the dour (and very frightened) child until they found the antidote.
Harry was, to say the least, not very enthusiastic about this predicament and hoped they could find the antidote soon. Very soon. Severus Snape wholeheartedly agreed (for the first and only time) with Harry Potter.
The day after the accident, Harry and Baby Severus were sitting at the end of the Gryffindor table closest to the door. Harry had absolutely no idea what to give the small child. Should he give him anything and everything from the table like Dudley had been given? Or, should he give Severus a piece of burnt toast as Harry, himself, had been given? How much did children eat, anyway? Dudley had always eaten too much and Harry always too little. What was in between? Harry really didn't understand why he had been given the job- he was only sixteen, after all, and had to go to class and do homework and he had Quidditch and Captain Duties and Hermione already harping on him about their NEWTs next year and- instead of a teacher. Dumbledore would have probably been the better choice, Harry grumbled as he gave the kid beside him a banana.
Severus Snape ate the banana warily, eyeing Harry as he chewed on the fruit.
Harry, however, paid the child no attention. He figured that his professor knew how to take care of himself and would only be angry later when he realized that Harry was babying him.
When it was time for Harry to go to class, he had no idea how to get the attention of the child. His aunt had always baby-talked to his cousin while Harry had been objected to harsh words and threats of being locked in his cupboard if he didn't get moving. So, Harry went with the lesser of two evils and said dryly, "Well, come on, then."
Hermione scolded his cold treatment at the child, but said child followed dutifully after Harry, grabbing his robes so he wouldn't get lost in the crowd.
Harry was even more lost at that. Surely Harry would trip. Aunt Petunia had carried Dudley most places while Harry struggled to keep up; he was never allowed to clutch at her clothes. Picking up Snape would cause embarrassment to the teacher later on, but tripping would hurt either or both of the two.
Harry was so confused.
And then the little boy needed to use the potty.
That threw Harry through a loop. What was he supposed to do? When he was Severus Snape's age Aunt Petunia had shown him how to use the toilet once and then expected him to learn from that. If he wet his pants, his punishment was to stay in the wet, smelly clothing as he was locked in his cupboard.
So, Harry excused himself from Transfiguration Class to take the little boy to the bathroom. There, he stared at Severus, then at the toilet, and then back to the child.
Harry really wanted to kill the headmaster at that moment.
Lunch was just as bad as breakfast. Harry had no idea what to feed a child.
Hence, Harry piled small portions of food on the child's plate and told him to, "Have at it."
Severus Snape, reluctantly, ate only a small portion of the (already small portions) of food.
Then he had a temper tantrum in the middle of the afternoon. Harry tried very hard not to spank the child (or hit him about the ears) because he remembered how much he hated that and he figured the de-aged man would not appreciate that much, especially in front of witnesses. He was excused from class and he hastily made it back to his dorm. He figured the little boy was just tired and placed him in the cot.
Severus soon fell asleep, and Harry just left him there as he worked on his homework in the common room.
Bath time was a nightmare. Harry had, at first, had the water way too hot, then way too cold. How was he to know what the water temperature for a baby should be? All he remembered was cold, dirty water as he washed himself after Dudley had been done. Severus nearly drowned no less than eight times because Harry had no idea how to hold a small child while they bathed. Harry then quickly rinsed the soap from the little boy after the eighth time and quickly- and a little roughly because he was getting a touch frustrated, even though he knew that was a poor excuse- dried Severus before dressing him in green footie pajamas.
Bedtime, though, was the worst.
Toddler Severus would not sleep. Harry couldn't sing a lullaby- he had no musical ability plus he knew none to begin with- and had no idea how to get a child to fall asleep in the first place. Holding the child seemed to work- at first. His roommates tried to give him advice, but nothing worked.
So, Harry did what his aunt had done to him; he placed the child in the cot and left him there. Harry, of course, felt horrible, but reasoned that, hey, if it worked for him, then it would work for the de-aged Potions Master.
After all, it's what we know and have grown up with that we use later on in life.
A/N: Just read some turned-into-a-child!fics and noticed they were kind of all the same. Just a little parody to get the juices flowing, even if it's not all that funny...