A/N: Inspired by tumblr user jilyfish. Enjoy!
"He's not going to do it."
"He said he would."
"Well, he's full of shit and he's not going to do it," James insisted, but he still looked hopeful.
"Are we really putting anything past Sirius? What wouldn't he do for five galleons and a laugh?" Remus pointed out.
"Well, for one, he wouldn't show up shirtless to Transfiguration class and face McGonagall's wrath."
"Sure about that, Prongs?" A voice rang out loud and clear from the back of the classroom. In the doorframe stood a smirking Sirius Black.
"Well, judging by the fact that you currently are wearing a shirt, yeah, I'd say I'm pretty sure," James shot back.
"This was just until I got here," Sirius Black said. "I couldn't risk one of the other professors seeing me and making me clothe myself before McGonagall got to see me in all my bare-chested glory."
"Well, you're here now," James challenged.
"Good point." In one, fluid motion, Sirius pulled his shirt over his head.
"Pete, hold onto this for me, wouldya?" He said, throwing the garment onto Wormtail's desk. Peter stared, open mouthed.
"Impressed, Potter?" Sirius asked, sliding into the chair next to James.
"I have to admit, I am. And so is Mary McDonald, judging by the way she's staring at you."
Sirius grinned. "Excellent. Reckon I should ask her out after class?"
"Patience, my dear boy, patience."
"Oh my God." Lily Evans loudly made her entrance known.
"Ah, Evans, good to see you," Sirius beamed.
"Good to see you too," Lily said, taking a seat next to Marlene McKinnon. "Although I have to notice that I am seeing a little more than I'm used to."
"True, true. I s'pose you wish that it was James instead, but feel free to make the best of a bad situation and keep staring."
Marlene laughed out loud and Lily blushed. "Shut up, Black," she hissed, staring determinedly at a seemingly random page of her text book.
"Wait, what do you mean? What did you mean by that?" James whispered, while Sirius looked smug.
"Just referring to a little conversation I overheard between Lily and Marlene the other day, nothing to worry about."
"Shhh, McGonagall's coming!"
The Transfigurations professor entered the room, her black cloak swirling behind her. "Right, sixth years, turn to page 98 and get started on-." She stopped in her tracks.
"Yes, Professor?" Sirius asked, his face the picture of innocence.
"Aren't you missing something?"
"What? I- Oh no!" Sirius gasped, looking down as though his was noticing his bare chest for the first time. "I must have forgotten to wear a shirt today! Oh, how utterly humiliating. How awfully degrading. Oh, please, somebody cover me!"
Professor McGonagall's lips twitched, threatening to betray a smile.
"Go and change. And that's thirty points from Gryffindor house."
"Only thirty? Wow, Professor, you must be feeling lenient today. Did anything-," he leaned forward, batting his eyelashes, "-make you change your mind?"
McGonagall's nostrils flared as the class struggled to contain their laughter.
"Out!" She roared, grabbing Sirius' arm and pulling him to his feet.
"Wow, Professor, it looks like you just can't keep your hands off of me after all. Okay, okay," he said hastily, catching her glare. "I best be off then."
The whole class watched as he dramatically walked out of the classroom, sighing loudly.
"By the way, Professor," Sirius added, turning around, "if anyone is to blame for this incident, it really should be Remus. He's supposed to be the Prefect here; how can he be trusted with that if he can't even be trusted to remind me to put on a shirt? He knows how unreliable I can-."
Bam! McGonagall sent sparks flying from her wand. Although they were obviously not intended to harm Sirius, it was enough to get him to take the hint. He turned and sprinted out of the room, poking his head through the door to wave one final goodbye to the class before McGonagall used her wand to slam the door shut.
"Bloody hell," James said, looking at the locked door with a look of utter respect and admiration. "He's mental."