Okay, so before anyone flips out about the incest, listen carefully: Mokuba is the only person Kaiba's ever loved. And Kaiba's so cold that Mokuba's the only person he ever COULD love…. So this could actually work.

Staring blankly at my computer screen, exhaustion tugged at my eyelids. My mind was blank due to the lateness of the hour—4 a.m. The mansion was silent, everyone but me sound asleep. Or so I thought.

"Nii-sama, when are you going to bed?" My little brother Mokuba asked from the doorway of my office. He wasn't really little; he was almost 15. But he was less than half my height, and thus why I call him my little brother. My Ototo-san.

"In a little bit, Mokuba." I said, not looking away from my computer. "I need to finish writing this." I began resolutely typing again, forcing my mind to form cognitive thoughts. Mokuba walked over to my desk and watched me for a moment. When my typing paused, he wormed his way onto my lap. "Mokuba, go to bed." I said irritably.

"Why?" He asked quietly. "This is the first time in weeks we've said more than a few words to each other." The words made a hot ball of guilt form in the pit of my stomach. With a sigh I wrapped my arms around my brother, holding him close.

"Alright….. you win." I murmured, resting my chin on the top of his head. "Tell you what—I'll go to bed, and you can sleep with me tonight, okay?"

"Okay." Mokuba said happily. I got up, picking him up like a small child and carrying him to my room. "Nii-sama?" He asked as we laid down on my king-sized bed.

"Yeah?" I asked, stifling a yawn.

He smiled sleepily. "I love you." The words stirred something in me—something that I didn't know, couldn't name and couldn't control.

"…..Don't fall asleep." I said softly, my fingers tangling themselves in Mokuba's messy raven locks.

"Why?" Mokuba asked, yawning.

"Because…… there's…… something I need to do." I looked at his sweet, sleepy and happy face and felt my heart jump into my throat. I had to do this…. Something told me simply saying 'I love you' back wouldn't be enough to show him how much he meant to me. I only hoped that…… "Just please….. don't hate me for this." I whispered, leaning down and pressing my lips onto his. His eyes widened in shock, but he made no attempt to push me away or stop me. After a moment his eyes slid shut, and he pressed into the kiss.

Feeling assured that this was the right thing to do, I closed my own eyes and trailed my tongue along his lower lip, my fingers still playing with his hair. He moaned softly, opening his mouth for me. I shivered at the sound and slipped my tongue into his mouth, exploring every inch of his mouth. He moaned again, moving his tongue to mine and rubbing them together, causing me to moan as well. His arms wrapped themselves around my neck, his small hands moving to run through my hair. Gods, I knew this was morally wrong, and yet it felt so right.

I broke the kiss after a minute, panting and licking the saliva from my lips. Mokuba was panting as well, his face bright red and his eyes half lidded.

"Nii-sama…." He whispered. "Please…. Do as you wish to me….." I shivered at those words, my hand moving from his hair to his face, cupping it gently.

"Are you sure….?" I asked softly. As much as I wanted, no, NEEDED this, I felt like I had to make sure.

He nodded. I nodded a little as well and moved my head down, trailing my tongue along the skin on his neck. He gasped, leaning his head away and giving me full access to his neck. I shuddered at the sound and closed my mouth over a section of the flesh, giving a gentle suck.

"A-Ah…. N-nii-sama…." He moaned. I sucked a bit harder, nibbling on the skin in my mouth. My hand moved down a bit further and rubbed his chest. "S-So….. good…." He moaned, panting slightly. I slipped my hand into his chest, finding one of his nipples and rubbing it gently with my thumb. After another few moments of lavishing his neck I pulled away, looking at the dark mark I'd left on him.

"N-Nii-sama….. don't stop…." Mokuba begged. I gently slipped his shirt off and licked his collarbone, leaving a wet trail down to his right nipple. I encircled it with my tongue several times, earning loud moans from my brother. Closing my mouth around the nipple, I sucked, then lavished my tongue on the nub again. After a minute or so of this I did the same thing to his other nipple. "Nii-samaaaaaaaa….." Mokuba moaned, his back arching towards my mouth. I removed my mouth and was about to move lower when suddenly I was pushed into the bed, Mokuba straddling my waist.

"M-My turn, nii-sama." He panted. I blinked; this was a welcome surprise. Mokuba dipped his head down, latching onto my neck like a leech and sucking violently. I moaned, my hand gently grabbing some of his hair.

"O-Oh gods, Ototo-san…." I moaned. He bit down, sucking again and then flicking his tongue on the skin. It felt so good…. I wondered if he was just a natural at this, or whether he'd had practice….. not that I cared if he had. He pulled away with a little popping sound, grinning at the deep bruise he'd left. Without pause he unbuttoned my dress shirt and licked all over my chest. I shivered, moaning again, my eyes closing as his mouth found an erect nipple and began teasing it with his tongue. I arched my back, panting, my mind a haze of pleasure. He moved to my other nipple and did the same thing.

After a moment he stopped, and I took a moment to clear my head, assuming he was done. But no. I realized his hands were working at my pants—and I blushed heavily when I saw that our activity had thus far left my dick hard as a rock.

Almost eagerly, Mokuba tugged my pants off, leaving me in only my boxers. He rubbed my dick through the thin cloth, and I gasped. It felt so damn good…..

"Nii-sama's so big…." Mokuba said as he hooked his fingers into the waistband of my boxers and pulled them down.

"M-Mokuba, don't say such things." I stuttered, embarrassed.

"But that's a good thing!" Mokuba insisted, moving his head to the base of my throbbing cock and dragging his tongue up. I closed my eyes and moaned lowly, my hands gripping the blankets beneath me. He continued to lick my shaft, his fingers massagging my sac. My mouth was wide open, a trail of saliva coming from it as I stared blankly up at the ceiling, panting and moaning. He closed his lips around my tip, swirling his tongue around it torturously.

"O-Ototo-saaaaaaaaan……" I moaned, my hips bucking a little into his mouth. He accepted this, moving his head down until he had taken my entire member into his mouth. I felt my tip hit the back of his throat and felt him gag, his throat closing around me. My eyes rolled to the back of my head. Mokuba began to bob his head, sucking and licking everywhere, his fingers still rubbing my sac. A hot ball began to form in the pit of my stomach, growing with every movement of my brother's head. "A-Ah….. M-Mokuba….. nn…. I-I'm…… g-gonna…..!!" My hips bucked, my back arched and my body tensed as I cummed heavily into his mouth. He released my now limp dick, swallowing the cum and licking his lips.

"Mm….. nii-sama, you taste good." He said. I looked at him—and a small smirk came onto my face. I grabbed him and pinned him to the bed.

"Now it's my turn to return to favor." I said, my hand rubbing Mokuba's hardness through his pajama pants. A sort of strangled moan escaped his lips. I pulled the pants down, then his underwear. "Mm…. you're bigger than I expected." I grinned a little, looking up at his bright red face as I stroked his cock slowly. He moaned, covering his mouth in embarrassment.

I dipped my head down, slowly taking my brother into my mouth. Hearing him moan "Nii-sama..!" in such a pleasured way made me shudder, my own cock starting to get hard again. I sucked, keeping my head stationary. My hand went to my cum-covered dick and rubbed, getting some of the thick fluid on the fingers. I proceeded to move my fingers to my brother's entrance, gently slipping the middle one inside of him.

"Nnnnn….. N-Nii-sama….. i-it hurts….." Mokuba moaned. I felt a pang of guilt, reminding myself this was necessary. Sucking a bit harder, I began pumping my finger into him, stretching him gently and searching for the little spot inside of him that would make him scream. He moaned a little, his mouth still covered by his hands. I licked his dick, flickering my tongue everywhere it could reach as I continued moving my finger in and out of him. "A-AhHH!" He gasped. I smirked a little, having only brushed the small cluster of nerves I was searching for. I pressed my finger deeper in him, knowing I had found my mark when I heard him scream for me. I slipped another finger into him, bobbing my head around his throbbing member. Scissoring my two fingers, I stretched him as my mouth continued to tend to his cock. "N-Nii-sama!" He moaned loudly, grabbing a handful of my hair. "I-It feels h-hot!" I knew he was close to cumming and slipped a third finger into his entrance. I didn't want to take any chances.

"Cum for me, ototo-san." I said around his member. He bucked his hips hard, releasing into my mouth. I swallowed his cum, finding it to be quite the taste and licking his limp dick clean. I then released him, removing my fingers from him. "Are you ready, ototo-san?" I asked, my hardened cock ready at his entrance.

"Y-Yes…." He panted, looking up at me with half-lidded eyes. I leaned over him, placing my hands on either side of his head. As I leaned down, pressing our lips together, I slowly pushed my throbbing member into him. He gasped into the kiss, his body tensing. I held back a moan, trying to restrain myself so I wouldn't hurt him more. "Relax." I mumbled, still pushing into him. When I was fully sheathed in him I paused, catching my breath and breaking the kiss. "Y-You okay?"

He managed a nod. "P-Please….. be gentle….." He whispered.

"Of course." I pressed our lips together once more, beginning to gently thrust into him. He moaned a little, whether in pain or pleasure or both, I couldn't tell. But I took the chance to slip my tongue into his mouth, rubbing our tongues together. He moaned again, and I began thrusting a little harder, searching for his sweet spot. It didn't take long to find.

"A-Ah! N-Nii-sama!" He cried, breaking the kiss and letting his head loll to one side. I moved a bit faster, moaning lowly myself. It was so tight and warm inside him. I kissed his neck, licking the skin hungrily. "H-Harder!" I obeyed, thrusting harder into him. He grabbed my shoulders, digging his nails into my skin. "I-I'm c-cumming!" He moaned, and a moment after I felt his hot cum splash onto my lower chest. His muscles tightened around me, and I moaned loudly. I rolled over onto my back so that Mokuba was straddling my hips.

"R-Ride me, o-ototo-san…" I panted. He placed his hands on my chest, moving himself up and down on my cock. I grabbed his hips, helping him move. My hips bucked up into him every time he pushed himself down, making him gasp and moan loudly. I moaned with him, the white-hot ball starting to grow in my stomach again. He practically bounced on and off of my swollen dick, his eyes closed, his mouth wide open. The sight was so erotic I nearly came then and there, but somehow I restrained myself. One of my hands left his hip and moved to his member, grabbing it gently and pumping quickly.

"A-Ah! N-Nii-s-sama!" He cried out. "I-I think I-I'm g-gonna c-cum a-again!!"

"Nng…. M-Mokuba…." I moaned, moving him quickly up and down on my member. "M-Me t-too……!!" A few thrusts later he tensed tightly, his cum flying onto my chest as he let out a strangled cry of my name. His muscles clamped around me, sending me over the edge and making me cum deep inside him. We were motionless for a moment, gasping for air and covered in sweat. Mokuba then fell onto my chest, and I wrapped my arms around him, holding him close. "…..Ototo-san."

"Y-Yeah, nii-sama….?"

"I love you too."