Gumball stretched. As he yawned in the early morning sunlight, Darwin got out of the bowl beside Gumball’s bed. Still foggy from sleep, Gumball began to do the one thing he had never done in front of Darwin before: change his  clothes. Not realizing his brother was still in the room, Gumball removed his shirt and shorts, bending down and presenting his briefs-covered butt to Darwin.
        “”Uh, dude? What are you doing?” Darwin asked nervously, having rarely seen Gumball so uncovered. Gumball turned towards the voice, confused by the fact that someone else was in his room. He was pulling off his undies before he turned, so he continued the motion while going to look at Darwin, showing off his flaccid penis.
        Darwin was, quite understandably, shocked. Being a fish, he had an internal penis, so he didn’t know what the small, fleshy tube hanging between his brother’s legs was.
        “Bro! What is that?” Darwin demanded. Awakened by the sudden outburst, Gumball snapped his hands over his cock.
        “It’s my peepee, don’t you have one?” Gumball responded, letting his hands drift away, uncovering his boyhood for further examination by Darwin.
“No, I don’t. Can I touch it?” Darwin queried from his knees as he  looked closer.
“Fiiiine,” Gumball said, secretly thrilled with the idea. As Darwin played with the feline’s above average member, he noticed several things about it. The skin at the top could be stretched back and forth. There were two balls in the sack underneath. As Darwin slid the skin up and down, up and down, something started to happen. Gumball’s penis started to harden and lengthen, pointing straight up into the air. Gumball stared in shock.
“Sorry! I didn’t mean to break it!” Darwin cried, “I’ll go get Mr. Dad!” 
Gumball fell back onto his bed dramatically, sure that  his peepee was broken beyond repair. As his father, the large pink bunny, walked in, Gumball threw an arm to his forehead in despair.
“...and I rubbed the top and it got all hard and I didn’t wanna break it…” Darwin sobbed. Richard knelt down and examined Gumball’s boner. 
“Not to worry, boys,” he announced confidently, “I know just the trick!”
He ran from the room at speeds the boys had only seen him use for the ice cream truck, and returned with a small bottle. Darwin left to fill the bathtub, distraught at his actions.
“The witch up on the mountain gave this to me,” he explained, holding up the plastic bottle with a parchment label glued over some brand logos. He opened it and poured some of the viscous liquid onto his hand. “She calls it lyubee.”
He dripped the stuff onto Gumball’s peepee, then pulled down his pants and did the same to his own, much smaller one. 
“Now you just need to rub it in like this,” Richard demonstrated, stroking his member as Gumball imitated.
“Nghhh… This feels soooo good,” Gumball said, moaning.
Richard grunted as his balls tensed, spraying a small rope of his cum onto Gumball’s face. Gumball lapped at it curiously.
“Salty, and… kinda good!” He exclaimed, sucking up more of it. His small body, too, began to tense as his orgasm neared. His decently-sized boner throbbed and released a large load of his seed into his mouth and onto itself.  Gumball sighed happily. This had been the best morning ever.