When Levi starts moving in kind with him, Erwin smiles around his cock. He knows how quickly Levi picks up on anything physical; he's not the slightest bit surprised that this is no different. He makes a soft humming sound, deep in his chest, and lets it reverberate up through his throat and into his mouth, onto Levi.

He's also not surprised at the sudden burst of profanity or how Levi clutches at his hair. Erwin wouldn't say it out loud, but he knows he's a damn good cocksucker, and he'd frankly be disappointed in himself if he didn't bring someone to climax relatively quickly. It didn't hurt that Levi was so keyed up and ready to go when he started, either.

There is no dodging, no attempt to get out of way. Erwin does the opposite: he plunges fully down on Levi's cock, letting his throat go lax as Levi shudders through his orgasm. It's only when it feels like Levi's done that Erwin swallows, his throat muscles constricting around the head of Levi's cock before he lifts his head up and off.

He has the dumbest, most pleased with himself look on his face. He is going to be insufferably smug about this for the next several days.