From what I remember, Kurt and Blaine have a drunken one-night stand. I think the fic actually starts off with them both waking up, Kurt being sort of goofy happy (because it was amazing) and Blaine apologizing because everything is hazy. (Like he might not even remember Kurt's name?) Then Kurt realizes that he doesn’t remember their night together, so he gets hurt and leaves…
One of the parts was Blaine saying that he’ll make Kurt pancakes in the morning, and Kurt’s like “I don’t like pancakes that much” and Blaine insists… Which is why in the morning when they wake up and they talk about breakfast Kurt realizes Blaine doesn’t remember anything…
Blaine is friends with Sam. And bits of the night keep coming back to him, and he realizes how much he likes Kurt and how amazing their night was… He tries finding him, and eventually remembers Kurt’s favourite coffee shop or something and meets him there. Blaine's got a line of "I'm sorry I took so long." at the end.
I've been desperately searching for it- any help is so appreciated! Thank you!
Edit: Someone found it! It's actually a section from now I know my ABCs (next time won't you sing with me)
by VilliageIdiot. Link is here: http://archiveofourown.org/works/1032097
Just scroll down to "Tequila Makes My Clothes Come Off"