Remus was minding his own business, heading back to Gryffindor tower, mentally going over his Arithmancy notes, when someone grabbed him by the arm and yanked him into a deserted corridor.
"I need your help with something, Moony," said Sirius.
Remus raised an eyebrow. Those words were usually directed at James. "What?" he asked warily.
Sirius rolled his eyes at Remus's suspicious tone. "Just a little experiment, Your High Holy Prefectliness. I promise it won't hurt, and you won't get into trouble. I just need to figure something out."
The sceptical expression on Remus's face did not diminish. He had known Sirius Black for more than four years, and had heard such promises before.
"OK," Sirius continued earnestly. "The thing is, I need you to kiss me."
Shock registered on Remus's face for only a split second before he clamped down hard on his emotions. "What? Why?"
"Because I think I might be a shirt-lifter. I figure snogging a bloke is the quickest way to find out for sure."
Losing control of his facial expression once more, Remus gaped at him.
Sirius's tone suggested that the possibility held no more than mild interest for him, as if he were speculating about which Potions ingredients, if burned, would produce the most interesting colour of flames. But then, Sirius had never cared much about what other people thought of him, apart from his three best friends, and sometimes not even Peter's opinion counted for much.
"So?" Sirius said impatiently.
"This couldn't wait until we got back to the dormitory, so you could find out with Prongs or Wormtail?"
"I don't want to kiss Prongs or Wormtail," Sirius snapped, then bit his lip, realising how this must have sounded.
Remus's stomach did a small backflip. "So -- you want to kiss me?"
Sirius shrugged. It was a shrug Remus recognised. Sirius was Playing It Cool. "Maybe a little. C'mon, Moony. It'll just take a second, and I promise I'll never tell anyone, not even Prongs!"
Remus shook his head. "No. Sirius, I -- no."
Because it's you, Remus thought. Because you're Sirius bloody Black and you make my belly squirm when you smile at me. Because what if I do kiss you, and you decide you don't like it after all, but you can tell that I do, and then you'll hate me and I'll have lost the most brilliant, wild, lovely thing in my entire life? Because I want to more than anything, but I'd rather not do it at all than do it once and spend the rest of my life knowing what I'm missing. Because I love you so much I can feel it in my elbows, and who ever heard of love-struck elbows? It was all simply too ridiculous.
"Because I -- I've never kissed anyone," Remus stammered, grasping wildly at a passing excuse. "I'd be rubbish, and you might decide you didn't like it on that account."
A wicked grin lit Sirius's face, causing Remus's belly to do a few more acrobatics. "It's dead easy, Moony, I swear! I'll show you how it's done."
Sirius's face was suddenly very close. Remus wondered if Sirius could hear his heart pounding or see the terror in his eyes. He stared at Sirius's mouth.
Just for a second, Remus told himself. He won't know, and this might be the only chance I ever get. "OK. But if it's rubbish, I told you so."
Sirius's grin widened as Remus closed his eyes, pursed his lips, and leaned in to press his mouth firmly against Sirius's in a quick, dry peck.
When Remus opened his eyes once more, he saw an exasperated Sirius glaring at him from very close-to.
"That was rubbish, Moony," he said. "I'm disallowing that one. You have to do it properly. Like this --"
And suddenly his mouth was pressed to Remus's, lips parted, and Sirius's tongue was grazing his lower lip. A rush of heat suffused Remus's body. He could not help himself. His mouth was moving, opening, responding, and Sirius's tongue was teasing his, as his hand fastened on Remus's arm.
Sirius drew back, an odd look on his face, to gaze at his flushed and panting friend. "Moony -- are you a shirt-lifter?"
"What? No!" Remus jerked away, poised to flee, but Sirius held him fast. "I'm -- I'm not anything, Sirius! I'm not allowed -- Who'd want to be with someone like me?" he said plaintively.
Something flickered in the depths of Sirius's eyes, and then his mouth was on Remus's again, hands sliding over his shoulders and down his back, pulling him close. All resistance evaporated, and Remus sagged against his friend, because everything he had ever wanted was happening right now. Except --
Remus pulled away again, eyes pleading. "Stop it, Padfoot. I don't want to be your bloody 'experiment'."
A slow smile curled the corner of Sirius's kiss-swollen lips. "The experiment's over, Moony. I found out what I needed to know."
"You did?" Remus asked warily.
Sirius nodded, grinning. "Now that I'm a confirmed shirt-lifter, the next order of business is for me to find myself a boyfriend. What are you doing tonight, Moony?"
Words failed Remus, but his answer needed none. A slow smile blooming over his lips as he leaned in to capture Sirius's laughing mouth once more.