Private Affairs

A:N Warnings: Voyeurism (Levi watching a ~seemingly~ private affair), rough sex, implied authority/power dynamics, established relationship (between Erwin and reader), praise, creampie, a brief bite, Levi wants reader and Erwin and I'm not sorry about it, so mentions of Levi fantasizing m/m as well.

Levi shouldn't be here.

The hallway is cold, dark, dusty. Filthy, like him. There's an immoral weight bearing down on his shoulders, heavier than the world itself. Envy and lust curl around his throat in the same way a fist cinches around yours.

He. Shouldn't. Be. Here.

But the moment his eyes found you, the silky, naked planes of your back rolling, arching, catching firelight, he was cemented to the floor.

He can see everything through the door crack: hands in your hair, the curve of your breast, the perfect heart shape of your ass pressed against the Commander's desk. And he can see Erwin, too, broad shoulders eclipsing the light, golden hair falling against his forehead, brawny arms flexing as they move, touch.

Intimate, private affairs happening right in front of him. He didn't even know the two of you were fucking when no one was looking.

"Missed you," your arms wind around Erwin's neck, lips slanting over his just perfectly. A routine, a pattern of kisses that look so familiar.

"I had a feeling you were getting a little needy for me."

Erwin's laugh slices through Levi's chest. The sound makes him hurt, makes his jaw and fists clench.

He doesn't know who he's watching. His silver eyes are dancing between your bodies, for a moment caught on Erwin's plush chest, then stuck on how the fat of your thighs spreads over the desk. He watches how lips trail down your neck, how your hands tug and pull Erwin closer, one leg looping around his waist.

Levi has imagined you both like this, albeit separately. And with his hands skimming over your nakedness.

It would be a lie to say the coupling before him wasn't better than his dreams. You look so pretty in Erwin's arms, nipples brushing downy chest hair, smile pulling at your cheeks. Erwin is exorbitant against you, appears larger, like he's about to engulf you and make you one with his muted, golden glory.

Levi is jealous of both of you. Especially when you lie back against the desk, breasts spilling out in front of his eyes until they're enveloped by Erwin's hands and mouth.

Levi wants to feel your nipples against his tongue. He wants to feel Erwin's lips against his chest.

"What a pretty picture you are, darling," Erwin is drinking you in, calloused hands pawing at your breasts. He doesn't know how poignant his words are. He doesn't know that you're on display for more than just him.

"So are you," you tease, fingers threading through his dark undercut, "I couldn't—," you gasp and giggle as his head dips lower, tongue treading along your stomach, "couldn't keep my eyes off you today."

Levi has so many retorts for himself over that line, about how his eyes shouldn't be—fuck he's tired of his guilt already; like he would ever deny himself the brief pleasure of watching you, perfect, darling, you, get fucked dumb on Erwin's desk.

"Hm, is that so? Caught up thinking about how your Commander was going to spread you open tonight?"

Levi has to stop himself from matching your moan.

His cock grows hard, thumping against the seam of his white trousers as you do, indeed, spread your legs for your Commander to fit between them. Erwin's face somehow looks even more handsome when surrounded by your supple thighs, roman nose peeking over your mound before burying against your clit. He's down on his knees in worship of your cunt.