The fourth time it happens, Blaine's prepared. He survived a conversation with Burt, which might have been the scariest moment of his life. He's always liked Burt and has never been afraid to go talk to him. Ever since he met Kurt, Burt has been more of a father figure than his own father ever has. Asking Burt Hummel for permission to marry his son is something else than talking to him about prom outfits though.

However, Blaine had not expected Burt to react the way he did. The man had been surprised of course, but he hadn't gotten angry or told Blaine he was insane like most people would have. Instead he'd treated him as an adult during the whole conversation. He'd asked him if he was sure about this, told him there was no rush if he was certain he wanted to be with Kurt for the rest of his life.
"I know that," Blaine had responded, "but proposing to Kurt doesn't mean we have to get married immediately. I don't mind if we have a long engagement. I just want the world to know that we belong together and I want Kurt to know that I want to be with him for the rest of my life."
Burt had been quiet for a while after that, but eventually he'd looked Blaine in the eye and told him that if he really loved Kurt that much, he wouldn't dream of keeping the two of them apart.

He'd gone ring shopping the same day, accompanied by Sam and Mike. The ring is now safely hidden in the glove compartment of his car, which is parked in front of the church, where they're waiting for the wedding-that-will-turn-out-not-to-be-a-wedding-after-all to start. It's kind of difficult to focus on the ring at the moment though, with Kurt's hands all over his body and his tongue in his mouth.
"I know fooling around at a wedding is terribly cliché, but I just can't help myself. You look so good in a suit, Blaine." Kurt's voice is so low and scratchy, Blaine can't help but moan.
"God, Kurt, I don't mind. I don't mind at all." As soon as he finishes his sentence, he pulls Kurt closer and kisses him hungrily. He wants to put his hands in Kurt's hair, but he can't risk messing it up right before the wedding, so he lets them wander to his ass instead and squeezes. Kurt moans, his hips bucking up into Blaine's.
"Shit, Blaine, I wish I could fuck you right now." Blaine almost loses it. His hands move up from Kurt's ass, frantically trying to pull his shirt out of his pants. He just needs to feel skin or he'll go insane.
"Fuck, Kurt, you can't say things like that to me unless you want me to come in my pants five minutes before we have to attend a wedding."
Kurt pulls his mouth away from where he was kissing Blaine's neck, but before he can say anything there's a tap on the window.
"For heaven's sake, please tell me that's not Tina again," Kurt groans in annoyance. "I thought you talked to her about her crush on you?"
"I have," Blaine assures him, "I swear I have, but -"
"Hey, can you two wrap it up?" Mercedes asks as she pulls the door of the car open. "The wedding is about to start and I need my arm gays."

As he stumbles out of the car, holding his coat in front of him in a desperate attempt to hide his boner from sight, Blaine remembers he was actually planning on proposing before the wedding. That's why he asked Kurt to go sit in the car in the first place, so they could have some privacy. Granted, it wouldn't have been the most romantic proposal, but he was tired of waiting for the right moment. There was always something off, something keeping him from asking the one question he's had on the tip of his tongue for months now. So he figured if the right moment didn't come, he'd have to create it himself. After all, if Kurt said yes, it would be perfect, no matter the circumstances in which the proposal happened.

None of that mattered now, though, because as soon as they'd climbed into the backseat of the car, Kurt's lips had been on his and that had been the end of his coherent thought process.

Suddenly he realizes Kurt and Mercedes are having a conversation and he's missed most of it, lost in thought. Whatever they were talking about, they don't seem to have noticed he wasn't paying attention. Mercedes loops her arm through his and says: "Let's go! This outfit needs an audience." And that's the end of it. He'll have to create the perfect moment another time.