Goten and Trunks ran into the house. Both were shirtless, having just come from training. They ran to Gohan's room, wanting him to play with him.
But when they got there, they saw Gohan, in his bed, pumping the largest erection either of them had ever seen. His dick must have been 14 inches long, and it was surrounded by a dark thick bush, and under them a large pair of hairy testicles. He had a treasure trail leading up to his belly button, his nipples were dark pink and hard, and he had a lot of armpit hair.
"Wooahh." The two boys said in awe.
"What the.." Gohan yelled as he tried to cover himself with his blanket, "what are you guys doing in my room?"
"We wanted to play with you Gohan, but now I want to know what you were doing." Goten replied.
"What, no, get out of here!"
"Please Gohan, neither Goten or I have a penis as big as yours. Can you please show us?"
Gohan sighed, and reluctantly he uncovered his crotch.
The two boys stared at the 14 inch member, and then Trunks took his pants off, with Goten following in suit.
"Woah, what are you guys doing?"
"We want to do what you were doing. Can you show us?"
"Wait, you mean jerking off? You guys are 13 and 14 and you don't ever masturbate?"
"No, so you should teach us."
Again, Gohan sighed, and he reached down and gripped his erection. He pulled up the foreskin and said,
"This is called foreskin. You pull this back and forth over the head of your penis with your hand to masturbate."
Both boys quickly grasped their hardening dicks, and began pumping them. When they reached their full size, Gohan was surprised to learn that Trunks was 9 inches long at 14 and his little brother was 8.5 inches. Trunks had a growing bush, and some hair around his sac, while Goten had less pubic hair and no hair on his balls. Both began pumping in earnest, and Trunks was the first one to say,
"Gohan, I feel something weird!"
"That's good, that means you're close to cumming."
"What's that?"
"Don't worry about that now, just keep doing what you're doing, both of you."
Trunks and Goten kept jerking off, until finally Trunks came with a scream, a small amount of cum dripping into his bush. Soon after, Goten orgasmed too, but with no cum.
"Why didn't anything leak out of my penis?" Goten asked, upset.
"It's because you're not old enough yet. And trunks only had a little bit too. You will both have a lot when you grow older, especially because your Saiyans. That's also why you have such large cocks. Most normal humans have 5 inches, rarely getting to six inches, but you two both have nine or close to it."
"Wooah, that's so cool. And so you would cum a lot too, Gohan?"
"Yeah I do, I guess."
"Can you show us?"
"Come on, teaching you how to masturbate was much farther than I should have gone, not this."
"Please?"
"No."
"What if we do it for you?"
And with that the two Saiyan boys jumped on the older boys cock, Trunks placing his hand on the large member, and Goten placing it on Gohan's hairy sac. Trunks curiously licked the member, and Gohan moaned.
"Goten, Gohan likes it when we put our mouths on him!"
Goten immediately took one of the hairy testicles in his mouth, and Trunks placed his mouth on the head of Gohan's straining member. Trunks took in as much of the 14 inches as he could, getting down more than halfway before he had to stop.
The two boys continued pleasuring the older teen, who had never felt anything like this in his 19 years alive. Soon, he yelled,
"I'm cumming, and the two boys came off Gohan's crotch to watch. However, Gohan came long and hard and far, covering both the boys faces and chests in his cum.
At that exact moment that the boys were getting covered in Gohan's seed, Goku walked in, wearing only his fundoshi.
"You boys were doing this while I was sleeping? Why didn't you invite me too?"
And Goku removed his fundoshi, revealing a soft uncut cock that measured 16 inches. He began pumping it, and it eventually reached a total of 22 inches.
All three boys stared at Goku and his enormous penis, which was surrounded by the largest bush of the four of them and sat above the largest, hairiest sac too.
"So, who thinks they can beat this?"
Gohan stood up and began transforming into a Super Saiyan 2. While he went through the transformation, the other three watched as Gohan's armpit hair, treasure trail, pubes, and sack hair turned gold along with the hair on his head, and they saw his dick stretching and growing. When he was done, his dick rested at 24 inches. Goten and Trunks followed his lead, and both grew to 11 and 12 inches respectively. Then, the two fusioned as well, ending as Gotenks Super Saiyan 3, with a total penis size of 23 inches.
"Not bad, the three of you. Let's how I do."
Goku began screaming as the yellow lights surrounded him. He transformed to his Super Saiyan 3 form, and his dick swelled to a demonic 36 inches.
"Sorry boys, guess I still win."
Unable to hold it in anymore, Gohan pounced on his father, barely able to take in the first testicle from his large sac. Gohan licked and sucked on the hairy orb, and then moved to the next one.
Watching this, Gotenks moved to Goku's penis and took the head in, which was so wide the fusioned boy was barely able to take it in. He tried to take in more, but he simply couldn't. He got off, and Gohan stood up. He moved to place his ass on Goku's dick, and Goku pushed the head in. As a SSJ 2, Gohan barely felt any pain, and so Goku began to push in. After several long minutes, Goku was balls deep within Gohan, and the two men's hairy sacks were slapping against each other.
Now, Goku was standing, supporting Gohan who was sitting on his dick.
"I'm proud of you for being able to take it all in son, and I'm proud of your manhood."
"Thank you father."
Then, Goku lifted his son and slammed him back down on his three foot cock.
Gohan screamed, as he had an entire cock rubbing against his prostate at all times.
Then, Gotenks jumped on Gohan and impaled himself on the two foot cock. He went down until his large sac slapped against Gohan's. Gohan screamed in pleasure from both sides, and he began fucking the combined form of his younger brother and Trunks. The three went at this for 7 hours, their Saiyan abilities increasing their durability. Eventually, Goku came within Gohan, so much so that cum flowed out of Gohan's hole like a river when he got off his fathers dick. Gohan also came within Gotenks, who was so tired he quickly reverted back to Goten and Trunks, although both were still Super Saiyans. They still hadn't came yet, so Goku took Goten's 11 inches into his mouth and Gohan took Trunks foot long cock into his mouth. Both sucked on the penises with unbelievable speed, the youngest pairs of testicle slapping against their pleasers' chins. Eventually, both boys also came with a scream, unloading into Goku and Gohan.
All four reverted to their normal forms, and Goku patted each of them on the back.