Additionally, I'm a day late and a dollar short for April Fools Day, but I wrote this anyway. In which Sirius gets it but good.
Sirius shifted a little, but didn't wake up entirely. After being poked again, Sirius cracked an eye to see Remus leaning over him, his silhouette familiar even in the pre-dawn light.
"Wa're y'doing?" he murmured. "Still dark. G'back t'sleep." He snaked an arm out from under the blankets and tried to tug Remus back down.
"I want you to tell James," Remus said.
"What!" Sirius sat up so fast he nearly sent Remus toppling off the bed.
"Keep your voice down," Remus ordered.
"What do you mean, tell James?" Sirius demanded in a harsh whisper. "What happened to 'it's a really big deal, Sirius' and 'you can't tell anybody, Sirius' and 'I'd rather die than have people know I'm sleeping with you, Sirius', what happened to all of that?"
"I've changed my mind," Remus said. "And I never said that last one."
"Changed your mind?!" Sirius hissed. "Lost it is more like it!"
"If you're serious about this, tell James," Remus commanded. He bent down to silence Sirius' spluttered protests with his lips. "Consequences for refusing," he whispered against Sirius' mouth, "are dire. And very lonely."
Remus slipped out of Sirius' bed before he could form another protest, and Sirius flopped back against the pillows, now thoroughly awake.
The next afternoon, Sirius caught a rare moment alone with James in the dormitory. Cursing his boyfriend's new melodramatics internally, Sirius cleared his throat and swallowed when James looked up expectantly.
"I've something to tell you," he said. "It's about me."
"Are you finally going to admit to being the one who returned my cloak covered in mystery crumbs?" James asked.
"Er, no," Sirius said, "it's about me and Remus…"
"It'll be about the Map then," James sighed. "Although honestly I'm surprised Remus was involved…"
"No, it isn't about any of those things!" Sirius interrupted impatiently. "It's important. James, Remus…I mean I'm…he's…we're shagging."
"Really?" James said. "Bully for you, who with? It's that Ravenclaw isn't it, the Chaser? I bet Remus is pulling that Hufflepuff…"
"You aren't listening to me, Potter!" Sirius shouted in exasperation. "WE'RE shagging!"
James stared at him.
"EACH OTHER! We're queers! Poufs! Bloody SHIRT-LIFTERS!"
James' eyes flicked quickly from Sirius to Remus' bed, then to Sirius' bed, but then on the way back to Sirius got snagged on the calendar and narrowed.
"Good one, Black," he said. "Nearly had me."
"What?" Sirius glanced at the calendar, cringed as he saw 'April 1' marked in block letters, then looked back at James. "No, I'm not kidding."
"Ha ha, joke's over," James waved him off. "I'm not falling for it."
"James, listen to me," Sirius said desperately, "I know this is a really poor timing, but I'm honestly telling you the truth, Remus and I are sleeping together!"
"Did he put you up to this?" James asked.
"Yes, sort of, but not…" Sirius took a deep breath and attempted to remain calm. "In the sense that if I didn't tell you he would break up with me, yes, Remus did put me up to it."
"Thought so, has his style written all over it," James nodded. "Intriguing, but largely improbable. I'll tell him I nearly fell for it."
Sirius kept at James until his hair was hexed green, but in the end was unsuccessful. Remus was nowhere to be found either, and Sirius crawled into his bed not long before midnight, very frustrated and steeling himself for a rough scene with Remus. Remus didn't make threats often, but when he did, he backed them up quite effectively.
Hoping to will himself into sleep, Sirius relaxed against his pillows and closed his eyes. It wasn't long before Sirius heard the edge of his bed hangings being moved aside and his mattress shifted as someone else climbed on.
"Well?" Remus asked. "Did you?"
"I tried," Sirius said, keeping his eyes shut so he wouldn't see the curve of Remus' body as he crouched on the bed or the way his fringe was always in his eyes. "I told him, over and over, but he wouldn't believe me."
"That's disappointing," Remus said. "Nice hair, by the way. Suits you."
"So I guess this is the part where I'm very lonely?" Sirius inquired tightly. Remus didn't answer, and Sirius cringed. After a moment, however, the mattress shifted again, and Sirius was surprised to feel a warm body press against his chest. He opened his eyes to find that he had a double armful of werewolf nuzzling his neck.
"What?" he asked. "I don't…"
"April Fools," Remus grinned before tugging Sirius' head down to make it up to him.