"You know," drawls Kakashi, "when I smoke, I like the satisfaction of knowing I do it to myself."
Asuma snorts, the cigarette briefly bobbing at the corner of his mouth before he plucks it. "Go ahead."
Kakashi arches his one visible eyebrow; he makes a show of taking the cigarette, and lifting it to his face, and then... nothing.
Asuma chuckles, shaking his head. "You could also take off your mask, you know."
"I could," Kakashi replies placidly.
He doesn't.
Asuma watches him for a few seconds, and then he leans forward, takes a deep drag, and tugs Kakashi closer. Beard against mask, it's a scratchy kiss. Asuma blows the smoke slowly through the cloth; under his lips, Kakashi's quirk up in amusement.
Second-hand smoke isn't all bad, finally.