This fic is part of my Crazy Game verse, so here's the setting:

Finn and Kurt have slept together. Finn isn't ready to fully accept his orientation. Being step-brothers would hinder the possibility of being in a relationship, anyway. They can't be together, then, even if they have strong feelings for each other.

Finn got back with Rachel, in an attempt to forget Kurt. Kurt is in a relationship with Blaine, who finally reciprocated his feelings at the worst moment: when they started to falter.

Based on the song Sugar, We're Going Down by Fall Out Boy.

For the sake of this verse, Kurt is boarding at Dalton.

Disclaimer: I do not own Glee or any song mentionned in this fic.

Don't mind me I'm watching you two from the closet
Wishing to be the friction in your jeans
Isn't it messed up how I'm just dying to be him

Finn was hurrying up on his way back home. He couldn't wait to see Kurt, who'd be home early, this Friday. He didn't have any classes, due to some holiday – the anniversary of Dalton's foundation, or something.

It's been a while since he last saw Kurt: he hadn't come home last weekend, because he had to study for his exam week.

When Finn got home, he noticed Kurt's car wasn't there. He called his name when he got in the house, just to make sure, but he got no answer. Kurt wasn't home yet.

Finn has been looking forward to see him all week, so it broke him to see he wasn't there. He really needed him; even if he kept telling himself and everyone who asked that he loved Rachel.

He climbed up the stairs and got into Kurt's room, flinging himself onto the bed, breathing in Kurt's smell that still lingered on the pillows. He knew it was kinda creepy, but he needed Kurt so much, he wanted to feel like he was there with him. It was so hard not to be with Kurt, not to see him every day.

He knew it was partly his fault that they weren't together. He thought it'd be simpler if he went back to being a straight guy with a girlfriend, instead of being that dude who fucks his step-brother. He'd never have imagined, though, how hard it would be to repress those feelings, to always feel like something was missing. What happened with Kurt was more than just a hook-up, he realized, more than two horny boys wanting to get off. He cared deeply about Kurt – it was more than simple brotherly love.

He was so deep in thought, so absorbed by Kurt's smell, that he didn't hear the front door being unlocked and opened. He only realized he wasn't alone anymore when he heard feet climbing the stairs and voices. Kurt's and – was that Blaine's?

Finn cursed under his breath. He really didn't want to see Blaine. Since Kurt started going out with him, things were kinda tense between the two of them – he didn't know if Kurt had told him about what they'd done, and it was tough to see him with someone else.

Also, he didn't want to explain why he was in Kurt's room; the real reason was creepy, to say the least.

He took a quick look around the room, considering his options, and he took what he'd later call the second worst decision of his life – the first being letting Kurt go.

He jumped off the bed, dashing into Kurt's walk-in closet just in time to hear them enter the room as he was closing the closet's door. The sliding door didn't close all the way, though. He remembered Kurt asking Burt to fix it. He obviously hadn't gotten around to it yet, and so Finn had a full-view of Kurt's bed, where Blaine was sprawled, pulling Kurt on top of him. Both were giggling, obviously happy to have the house to themselves. Finn couldn't believe the situation he'd put himself in. Was he really gonna be forced to watch Kurt make out with his boyfriend?

But then Kurt, panting, struggled to take off Blaine's sweater. That answered his question: he wouldn't have to watch them make out.

He'd have to watch them have sex.

The thought of it made him feel like he'd been punched in the gut, and he had to brace himself against the doorframe not to fall.

Blaine took off Kurt's shirt, though, and Finn felt a tingle in the pit of his stomach. He hadn't see Kurt's body like this since that time, and he missed it so much. He just wanted to get out of hiding and touch him, feel him against his own skin.

But the fingers trailing on Kurt's back, the lips nibbling at his shoulders, they weren't his. Blaine was the one who was allowed to do that now, and the thought was enough to make him wanna shut his eyes closed and crawl in the back of the closet.

Until he heard Kurt moan.

Kurt's moans did things to him. Whenever he heard them, he couldn't think about anything else. He just wanted to hear more of them. It hurt to know he wasn't the cause of them, but he stopped thinking about that when he took notice of the bulge quickly growing in his pants.

He knew it was creepy, but he couldn't help himself. He'd needed Kurt for so long, and this made him feel almost like he had him again – as long as he blocked Blaine from his mind and focused on Kurt's moans.

On the bed, Kurt began grinding down against Blaine, exactly like he did that one time with Finn. Instinctively, Finn's hand flew straight to his crotch, palming his hardness through his jeans, trying to remember the sensations Kurt gave him that time.

He couldn't look away. He found himself wishing he was that friction in Kurt's jeans, wishing he was the one making him moan and arch his back like that.

Wishing he was Blaine.

He realized it was messed up, but he didn't care. He wanted to be the one who got to be with Kurt, to make him come like that.

He moved his hand over his cock faster, matching the rhythm of Kurt's thrusts, and he was glad Kurt was vocal in bed, because otherwise, they would have heard his heavy panting.

As Kurt reached the peak of his orgasm, his moans becoming erratic and breathless, Finn heard something that sent him over the edge:

"Oh, Fi – Blaine!"

He was pretty sure Kurt had just caught himself in the middle of moaning his name.

At the mere thought of it, of the fact that even though somebody else made Kurt come, he still thought about him, Finn came harder than he had in weeks – since Kurt, actually.

If the creepiness of the situation hadn't hit him yet, it would certainly now. Here he was, his pants sticky with come, in that hazy daze he always had after coming, in Kurt's closet, while Kurt cuddled on his bed with Blaine, only a few feet away. He couldn't get out now, he had to wait until they left the room, but the displays of affection were too much for him to bear. He sat on the closet floor, looking away from them.

He was in luck, though, because Kurt couldn't stand staying in sticky pants, so he took Blaine's hand and led him out of the room. Finn waited until he heard the bathroom door closing, followed by the sound of the shower, and dashed as silently as he could out of the room. He first made for his room, but decided he'd better pretend he just got home.

He didn't know if they could hear him from the shower – he didn't even wanna know what they were doing in there – but he made his way downstairs, wincing at the gooey feeling in his pants. He opened the front door and slammed it shut, calling Kurt's name loudly, then stomped upstairs.

When Kurt and Blaine got out of the bathroom, Finn did his best to look happy to see them, and not like someone who'd just watched them fuck.

He managed to escape Kurt's questions – "Tell me all the juicy gossips! How's Rachel? And New Directions?" – long enough to throw himself in the shower and get rid of his stained clothes.

If Kurt thought it strange that he took a shower in the middle of the day, he said nothing. After all, they'd just done the same.