"Watch your teeth."

Childe moans around his cock, but eases off at his request. Zhongli's gaze drops to his lap to find him watching back, a smirk firmly plastered across his face. Then, keeping eye contact, he dips forward and licks from the root to the tip, swirling his tongue around the crown.

Zhongli grunts. "Childe," he murmurs. It was meant to be a tease, a silly little game played because Childe came back in pieces. Zhongli was and still is, unenthused, particularly at the wily grin planted firmly on Childe's face as his cock rests against it.

"You should hurry—"

"This isn't meant to be a treat," cuts in Zhongli curtly.

"Could have fooled me." Childe shifts his face, pressing his lips against the side of Zhongli's cock for a nibble.

"No teeth—"

"Then finish your work. I'm dying to get my hands on you."

Zhongli's gaze flits to where Childe's artificial arm lies on the table, the case cracked open and wires sticking out, frayed at the ends. A disaster. Childe had walked into his workshop from a mission with the damn thing busted and ripped from his socket.

"Hours of work," he says then. "You realize that, right?"

"Then get to hammering."

"Childe." A chastise that lacks bite. Zhongli takes in the workshop and finds the coast clear. "Ajax," he whispers then, "You need to be patient."

"I—"

"Can you be?"

Childe's throat bobs. His eyes soften and he rests his cheek against the rough-worn linen of Zhongli's trouser leg. "Yeah," he breathes.

Zhongli arches a brow. "And my payment? I asked for you to warm my cock, not smother it."

A soft snort as Childe exhales, but when he smiles this time, it's lazy. "With my other hand behind my back?"

"Those were the terms. Behave."

And just like that, Childe settles. Zhongli hums as pets his hair, the thick leather of his gloves catching against his forehead as he brushes back sweaty bangs. Childe didn't even get a chance to bathe.

"You smell like machine oil," mutters Childe. "Mhmn." He likes it, that acrid and sharp tang. He often shoves his face into Zhongli's nape to seek it out.

"Darling," says Zhongli, cupping Childe's face with his other hand. He traces Childe's bottom lip, slipping in a thumb to part them. Childe's mouth is lax as the tip of Zhongli's cock is pressed to it. A sweet kiss to the tip before he settles, sinking down on Zhongli's length until it rests comfortably in his mouth. "There's a sweet boy for me."

It is dangerous. The Tasritsa has eyes and ears everywhere, and to have a Harbinger between his thighs in such a way is more than compromising, it's almost blasphemous. Still. He drags his fingers through Childe's hair, scraping at his scalp for a moment. A soft groan as Childe sinks to his knees, finding a comfortable position. His mouth is soft and yielding, the flat of his tongue pressed to the underside of Zhongli's cock.

A minor distraction, not enough to pull him away from his work. This was the game he'd meant to play originally.

"Stay there," he says, dragging his fingers down the tense line of Childe's shoulder. He stops at the joint and thumbs over the metal stump just below it. "I'll fix this up and then you can have your way with me."

Childe's eyes flash at that but he does as he's told, sighing around his cock as Zhongli leans back over his desk to resume his work.

His best tinkering is always done with the weight of Childe against him in one way or another.