This fic will be slightly more plausible if you picture Kurt with his early season 4 blond highlights.
"Ow! Sam!" Blaine yelped from in front of the stove as Sam smacked his ass while hustling out the door.
"I'll meet you outside NYADA after class for our bro date!" Sam called out, punctuating his statement with a slam of the apartment door.
"Why did I have to make friends with the one guy who doesn't get that ass slaps aren't appropriate greetings off the football field?" Blaine said to himself, flipping his omelet out of the pan and onto a plate. "Especially since we've been out of high school for two years now."
He took his plate and plopped down at their tiny kitchen table, deciding to just shove the incident out of his mind. He had more important things to focus on, like how to incorporate his newest bow tie into his wardrobe and what monologue to do for his Shakespeare class next week. By the time he had to ditch his plate in the sink and scurry out the door, he'd already started narrowing down the possibilities and worked his new tie into his current outfit.
Blaine couldn't believe his luck. He was walking down the staircase into NYADA's atrium when a glint of blond hair caught his eye. A quick second look confirmed that the figure he saw was wearing a red jacket that looked an awful lot like Sam's old McKinley letterman.
"Oh God, revenge is so sweet," he whispered, grinning in anticipation. "Please don't turn around, please don't turn around..."
Blaine walked quickly and quietly, hoping that Sam wouldn't turn around and spot him. Once he was close, he wound up enough to deliver a decent sting, brought his hand down, and chuckled softly in pleasure as he smacked Sam's ass.
Or, well, what he thought was Sam's ass.
"What the-" the guy whose ass he'd smacked exclaimed, whirling around to reveal-
"Oh my God, you're not Sam," Blaine said, horrified. One hand came up to his mouth involuntarily to cover his gaping jaw.
The guy was gorgeous. Brown hair with golden highlights, a red leather blazer that showcased his arm muscles, and a facial expression caught between anger and confusion.
Okay, so maybe that last part wasn't fantastic, but the rest of this guy was enough to make Blaine want to propose marriage on the spot. Even his ass had felt great under Blaine's hand – firm yet supple, as creepy to notice as that probably was.
"No, I'm not Sam," the guy said, quirking an eyebrow. "Is there a reason you wanted to sexually harass him, though?"
"It was supposed to be payback," Blaine said, flushing crimson. He spit out the rest of his explanation in a rush: "Sam's my best friend and roommate and he never got out of the habit of slapping people on the ass after playing on our high school's football team, so after he smacked me on the ass yet again this morning I thought I'd try to take my revenge, but then I screwed up and mistook you for him and now you're probably going to have me either expelled or arrested."
"Well, I was considering it," the guy said, and oh no, his smile was far too adorable for Blaine to handle at that particular moment. "But after seeing how flustered this mix-up made you, I'm willing to let it slide. I'm Kurt, by the way. You may as well know my name after getting to second base with me."
"Is that what second base is when neither partner has boobs?" Blaine wondered aloud, shaking Kurt's outstretched hand. "I've never actually gotten that far on purpose. Oh, and I'm Blaine. Nice to meet you!"
"I've never gotten that far either, I'm just guessing," Kurt said, still smiling that smile that made Blaine's heart do flips in his chest. "I also just wanted to make you laugh, you looked like you were about to either pass out or cry when I turned around."
"I'd just realized I'd smacked an incredibly cute stranger on the ass!" Blaine said, indignant. "Forgive me for not being totally composed."
"You think I'm incredibly cute?" Kurt asked, looking a little stunned.
"Oh God, I said that out loud?" Blaine said. He felt the blush return to his face. "I'm really pushing my luck today, aren't I?"
"I didn't say I was unhappy to hear that," Kurt said. "I've just been in kind of a boyfriend dry spell recently, that's all."
"Then you wouldn't mind if I asked you out for coffee?" Blaine asked, rocking forward slightly on his toes. "It's the least I can do after attacking you."
"Sounds wonderful," Kurt said, and either he'd have to stop smiling like that or Blaine was going to have to invest in a pacemaker to keep his heart beating properly. "Let me just go hunt down my roommate and tell her where I'm going."
"I'll wait here!" Blaine said, smiling back at Kurt. He reached into his pocket once Kurt was gone and pulled out his buzzing phone.
Dude. Where r u?! Ive been waiting 4 like 15 mins now!
Change of plans. Have a REAL date after trying to get revenge on you for smacking my ass this morning. Will explain later.
Blaine tucked his phone away as Kurt walked back up to him, linking an arm in his.
"I had to stop my roommate from coming over here and pepper spraying you for hitting me," he teased as they walked out the doors. "But I told her that if our date doesn't go well, she can get you when you walk me home."
"I guess that means I'll have to be on my best behavior," Blaine joked back, feeling weirdly comfortable around Kurt. "I'll keep my hands to myself unless you're going to fall into traffic and die or something, I promise."
"I knew you were a gentleman."
True to his word, Blaine was perfectly polite throughout their date, trying to make up for starting off on the wrong foot (hand?) earlier that afternoon. When Kurt leaned in and gave him a kiss on the cheek before heading inside his apartment later that evening, Blaine thought he might be able to float the whole way home.