A Lesson in Formation
Sirius burst like a hurricane wind through the heavy Hogwarts door into the sunshine- saturated afternoon, a disgruntled Remus in tow. He inhaled deeply, then exhaled with a loud whoop. "See, Moony?" he cried. "Sunlight! And fresh air! All things that a growing boy needs!" He turned to Remus and grinned cheekily. "This is what life outside the library looks like," he said laughingly.
Remus frowned. "Life outside the library is hurting my eyes," he complained. "And is also very likely going to give me a sunburn." He cast a longing look toward the building they'd just left, then started and turned abruptly when he felt warm hands gripping his shoulders. "What?" He couldn't completely keep the annoyance from his voice.
"You," Sirius began. "Have got to get outside more. I mean, look at this!" Sirius lifted a hand from Remus' shoulder and gestured out toward the lake, his other hand settling comfortably on Remus' back. "The sun is shining, the birds are singing--"
"Squawking, more like," Remus interrupted.
"--The water is sparkling," Sirius continued as if he hadn't heard Remus. "The clouds are a lovely cumulus shape..." He looked back toward his friend. "Don't you appreciate it in the slightest?"
"Cirrus," was all Remus had to say to that.
Sirius was a bit confused. "What?"
"Cirrus," Remus repeated.
Sirius tilted his head. "What is it? Why do you keep saying my name?"
Remus shook his head, exasperated. "Not you, wanker. The clouds."
"The clouds are Sirius?"
"No," Remus said, features arranged in a look of careful patience. "You said that the clouds were cumulus today. They're actually cirrus clouds."
"Oh?" Sirius looked up at the sky.
Remus nodded. "Those clouds are far too wispy and high up to be cumulus clouds."
"Really?" Sirius asked, eyes still trained upward.
"Yeah," Remus answered. "Cirrusly." He laughed a little at his own (admittedly lame) pun.
It took Sirius all of half a minute to comprehend the joke before he, too, laughed and cuffed Remus on the back of the head. "Come on, Moony," he said. "Let's go to the lake." He ruffled up Remus' hair and pushed him back a little before sprinting ahead and yelling, "Last one there's a hag!"
"No fair, you got a head start, cheater!" Remus laughed. He paused for a moment to smooth down his hair, and looked up at the sky. Well, he thought, it doesn't matter what shape they are, does it? They'll always be Sirius clouds. He shook one wrinkle out of his shirtsleeve and sprinted to catch up with his friend, chuckling to himself the entire way.