Blaine had always been a bit pee-shy. For some reason, he just couldn't pee in a public bathroom knowing there were other people there. Not many people knew about this- of course, it wasn't something Blaine particularly wanted advertised. He had told Kurt, though; they told each other everything.
Because of this problem, Blaine usually avoided the school bathroom at all costs. But he'd slept in this morning, and he couldn't hold it much longer. He had to give in. Thankfully, the restroom was empty during his fifth period study hall. He'd already begun his pee when he heard someone enter the bathroom.
Shit.
Blaine's stream immediately stopped. He silently prayed to Wizard God that no one noticed. Then he heard a voice from outside the row of stalls.
"Blaine?"
The boy's face grew immediately red. It was Kurt. "Yeah?"
"Oh, honey, do you want me to leave?"
"…Yes? No? I don't know."
"Blaine, you need to get over this. You can do it, I believe in you!"
"I…"
"Here," Kurt soothed, now in a stall. "I'll go first."
Blaine could hear Kurt's zipper going down, and soon after, the gentle tinkle of urine being expelled into the toilet. I can do this, Blaine told himself. He concentrated, and a moment later-
"Kurt! I'm doing it! I'm doing it!"
"That's awesome, Blaine!"
Once they were both done peeing, they shook off and washed their hands (BECAUSE THAT'S WHAT YOU FUCKING DO WHEN YOU TAKE A PISS). Kurt kissed Blaine chastely on the cheek. Blaine kissed him back, harder, and on the lips.
Kurt hummed happily. "Maybe we should have a little reward for the step you've taken today…"
Blaine, feeling patronized, was about to protest, when a well-placed hand revealed Kurt's intent. Oh… That's a big boy reward…
Soon they were smashed together in a stall, their lips locked and their hands fumbling at the clasps of each other's belts. Kurt pushed Blaine's pants down aggressively over his hard cock.
"God, Blaine, I love your cock," Kurt gaped. "I just want to touch it and worship all of it."
"Please," begged Blaine. "Oh, god, Kurt, please."
Kurt's fingers traced around the base of Blaine's cock, tickling at his balls, before ghosting lightly over the length. Blaine's hips bucked up at the touch. "More, Kurt, please!" Kurt removed his hand entirely. He made sure Blaine was looking at him when he licked his palm wetly, sucking on the fingertips. Blaine had to moan at the sight. Then Kurt gripped Blaine's cock firmly and started to pump- slowly at first, but gaining speed. Blaine moaned wantonly. The noises his boyfriend was making were going straight to Kurt's dick. He pushed his other hand down his pants, but Blaine slapped it away, pushing Kurt's pants down himself and slicking his hand with Kurt's pre-come. Kurt bit into Blaine's shoulder to stop himself from crying out too loudly as they stroked each other's cocks, bucking into the heat of each other's hands.
"Kurt, I'm so close…"
Kurt only nodded. Moments later, Blaine came, spurting into a well-timed tissue. With a few more tugs on his cock, Kurt was coming, too. They leaned against the wall together, coming down from their highs.
"Wow…" Blaine panted.
"Yeah…" Kurt replied.
And that is the story of the reason why Blaine gets turned on when he pees with other people in the room.