Henry was three years older than Dyson when Dyson moved into his house. At first he wasn’t at all impressed by his tubby little step-brother. Henry believed that he and his Dad had been getting along just fine by themselves. He didn’t want a new Mom and he certainly didn’t need an annoying little brother.

Before they moved in, Henry had assumed that it was his stepmom who would annoy him most, but Janice turned out to be nice. She wasn’t over-controlling, she didn’t try too hard, and she never pretended to be his Mom. It was her son, Dyson, who drove him mad.

The cute chubby little funster was all smiles on the outside. But, Henry saw through his cheerful and friendly disposition. He saw the devil inside of Dyson; he knew that he was a greedy, spoiled, selfish little brat. Henry hated his step-brother, but it didn’t take him long to work out how to get at him.

It was obvious to Henry, from the very first day, that Dyson had Janice wrapped around his pudgy little finger. He took note of how she bemoaned his appetite and weight, and then gave him whatever he demanded anyway. It was kind of the opposite of the relationship that Henry had with his father. Henry’s father was kind, but he was in control. When Henry’s father said no, he meant it. This was not the case with Janice and Dyson. Janice said no, and then Dyson got what he wanted anyway.

Dyson was twelve when he moved in; now he was seventeen. He was a senior in high school. His eighteenth birthday was in September, so he was the oldest in the year.

For five years Henry had put up with Dyson’s selfishness and gluttony. He had put up with his step-brother’s every wish being granted. He had had enough. He had watched Dyson grow from a chubby kid into a seriously fat teenager. Henry fully believed that Dyson was a fat, obnoxious, and selfish young man; who cared not a jot for anybody else's well being. As long as Dyson got what he wanted then that was all that mattered.

Henry plotted his revenge.

The plan started early. To Henry, it was obvious. If Dyson wanted more food, then he should get it. At first it was subtle. Henry offered to serve the ice cream after dinner, like a helpful son, and made sure to give Dyson an extra scoop. Henry knew that Janice was concerned about her son’s weight; she just lacked the required parenting skills to deal with it. Henry would help her with it. Henry would ensure that Dyson’s weight only kept increasing.

He served his little brother extra ice cream. He gave him extra portions of lamb chops. He ‘shared’ his candy with him, and always let him finish the bag of chips. He planted bottles of Cola in Dyson’s bedroom, and was always sure to let Dyson have all of the pizza dips.

Dyson’s belly grew. It expanded far beyond his waist. Henry was thrilled. Fuck you fat boy, he thought to himself, while handing Dyson another packet of Oreos. But, to Henry’s chagrin, Dyson never seemed to mind his weight gain. He wore his belly with pride. He chose to wear an orange t-shirt that barely covered his chest, let alone his stomach. Dyson paraded around the house, and school, with his ever expanding gut on display for everyone to see.

Henry had had enough. He had made a mistake. He had thought, years ago, that making Dyson fat was a way of getting at him; but it clearly wasn’t true. Dyson liked being fat, and Henry had only succeeded in enabling him. How could he have been so stupid?

It was the thirteenth of September, Dyson’s eighteenth birthday, when Henry sneaked into Dyson’s room. He looked at the unkempt single bed covered in soda cans and candy wrappers. He smelled Dyson’s pillow. He then sat down on Dyson’s bed among the litter and food trash. He felt his own bony ass sink into the groove that Dyson’s immense frame had carved into the mattress over the previous six years.

He reached under the bed and withdrew Dyson’s laptop. He flipped it open and was surprised to see images of other fat boys. It was a social media site for gay gainers and something called the Surplus. Henry had heard the phrase, but had been convinced that it was just a conspiracy. He shut the laptop when Dyson entered the room.

Dyson was tipsy and heavily bloated. His gigantic stomach sloshed from side to side. His birthday meal had been a complete success. Pizzas, burgers, fries, and pork chops had satiated him at first. But then, thankfully, came the pasta, sirloin, and sausage plates. This he had topped off with pumpkin pie, double cream, cinnamon buns, and a gallon of ice cream.

He looked down at his belly, and then he looked at Henry sitting on his bed. Dyson felt the anticipation in his belly and his asshole. “Thank God, you have come to your senses, brother,” he said.

Henry plowed Dyson’s huge fat ass. He plowed it good and hard. He watched in joyous amazement as the gigantic buttocks, that he had helped to create, shook and twitched and vibrated violently against his throbbing cock.

Dyson was filled with food and joy. He had never felt so complete before. He had ten thousand calories in his gut and ten inches in his ass. This was what he had been promised. His asshole overflowed with cum.

He loved his brother so much.