The brass knuckles ghosted a trail along Kirk's cheek. Sulu leaned down to whisper in his ear. "How does that feel?"
"Good."
"Good." Hikaru followed the path of his knuckles with his tongue.

Kirk lay on his stomach in nothing but his boxers with Sulu's nude form straddling him. He hadn't even known Sulu liked brass knuckles; much less that he used them this way. Naturally, Jim was a little surprised when Hikaru bought them on their last shore leave, and a lot surprised when he busted them out in the heat of passion. Not that Jim was complaining, of course. In fact, he enjoyed seeing this side of his…what was Sulu to him, exactly? Not his lover, certainly not, but fuck buddy didn't sound right, either. He settled for friend with benefits, although that didn't quite apply to them, either.

"Turn over," Hikaru whispered, then lifted off Kirk a little to allow him to do so. Sulu removed Jim's boxers, and then proceeded to systematically ignore Jim's cock. Sulu bit and sucked at Jim's neck, his nipples, his belly, the hollows of his hips, ran his brass knuckles along Kirk's chest and sides and thighs, touching with one or the other just about every part of Jim's body except for his cock.

"Come on," Jim whined. "I want you to suck my cock!"
Sulu's knuckled hand traveled up Kirk's body to his face and gave it a light slap. "You don't get to talk," he said. When he decided Jim had had enough torture, he ran his tongue along the length of Kirk's shaft before taking it in his mouth. Kirk moaned and pushed up into Sulu's mouth. Hikaru sucked down on him hard, causing Kirk to moan again. "Oh yeah," he breathed. "Suck that dick."
Sulu pulled away and slapped him, this time with a little more force. Tiny stars of pain burst in Jim's cheek. "I told you—you don't get to talk," Sulu said.

Jim was still half-dazed and reeling from the slap when Sulu finally lowered himself onto Jim's cock. As Hikaru moved above him, he returned to his senses. He thrusted up into his—dammit, what were they?—and Hikaru tightened around him, and it was more than he could take. "Oh, God, Hikaru," he said. This time, Hikaru didn't bother to remind him not to talk.

When they finished, Sulu lay on top of Kirk, still sweaty and refreshed and exhausted. He kissed Jim and gave him a light pat on the cheek with his knuckled hand before climbing off the man. He sat up and opened a drawer in his nightstand. Its contents caused Kirk's eyes to pop. The drawer contained pair after pair of brass knuckles—big ones, small ones, elaborately decorated ones, simple ones. Sulu removed the pair he'd bought their last shore leave and tossed it into the drawer with a "clink." When he turned back to Kirk and saw the shocked expression the other man wore, he asked, "What? You're surprised?"

"I didn't know you had this many," Jim remarked.
Sulu smirked. "Well, if you want to, we can go through all of them."
"Um…yes."
Sulu shut the drawer and lay back down next to his…oh, who cared what they were? This worked for them, and that was all that mattered.