I woke up, having heard the sound of my bedroom door opening and then closing. I opened my eyes and looked over to the doorway, where I saw the immense figure of my formerly "little" brother.

"Tyler," I hissed, not wanting to wake up our parents down the hall. "What are you doing in here?"

"Hey, bro," he said, casually, "I'm feeling kinda lonely. Would you mind if I slept in here with you?"

Without giving me any time to answer, he moved towards my bed, pulled aside the sheets, and climbed in. I didn't really know what to say; I wasn't crazy about the idea, but I didn't quite know how to say no to someone who could easily beat me up at his new size.

He climbed in my bed, and I could instantly feel the mattress settle as it adjusted to his weight, leaning over towards his side. I turned my back towards him, closing my eyes. "Good night, Tyler," I said, trying to get back to sleep.

After a few seconds of silence, I felt him scoot over closer to me, and he reached over and wrapped his arm around me. It was a large arm, like being hugged by my dad when I was a kid. He pulled me closer towards him, and pressed his body against mine. It was at this point that I realized he was totally naked. His smooth, muscled chest rubbed up against my back, and pressing against the side of my thigh I felt what I could only guess was his cock, as impressively large as anything else about him was now.

I quickly spun around and looked at him in the eyes. He had an innocent look to them, reminding me that he was still a boy, no matter how big his body had gotten. "Tyler, no," I said. "If we're gonna sleep like this, we need to keep our distance."

"I'm not tired yet," Tyler said, as he moved his hands down my back and towards my ass. He gave them a light squeeze, tugging at my boxers, finally ripping them off in one quick motion. There I was, lying next to my bigger brother, the two of us naked. It was at this point I realized that I, too, had begun to grow hard at this.

I began to take a second look at Tyler, his body lit by the moonlight leaking through my window. He was now undeniably hot, muscles all over his body having been developing quickly, but with the smooth hairlessness that should accompany someone his age. His feet were hanging off the end of my bed; he was truly a giant now, and, though I knew he would never intentionally hurt me or anyone else, he had a strength now that was almost frightening. And, of course, there was the matter of his manhood, which now, as he was lying on his back, stood straight up, at least fourteen inches long and nearly as thick as my forearm. Its slit was starting to secrete precum, and with each beat of Tyler's heart, it throbbed, as if to indicate it was ready to explode with just the right touch. At this point, I had to face the facts: no matter how much my brain said otherwise, no matter how weird it felt, physically I was beginning to desire my brother.

Tyler turned his head, the moonlight reflecting off his eyes in just the right way so that his pleas seemed extra sincere. "Please, Joe. I need you to help me."

At this point I realized I had to make a decision.