As you two slept peacefully, the clothes thrown off would lie atop one another. Your gothic dress and other outfits would like on top of Jacob's. Unbeknownst to you two, your little sister's spell had a tendency to spread to other clothing. The spell would flow from the threads of your dress into Jacob's clothes until both were now fully enchanted.
The sounds of the morning birds woke you up. The events of the previous night replayed in your head. Looking behind you, your found your plump rear housing Jacob's cock. It took a bit of maneuvering to make sure he wouldn't be disturbed by this but eventually you were freed. Standing up nude, you glanced over to the pile of clothing and began to reach to put on your things before pausing. You had always admired Jacob's physique. Maybe he wouldn't mind if you tried on his clothes for a while. It's not like he would know or anything.
Pushing aside your dress, stockings, bra and heels,your gathered his tank top, shorts, sandals and bracelet. Leaning down, his top reeked of sweat as you could feel yourself hardening at the thought of his sweaty body against yours. You began with his underwear, letting it hang around your waist. Next came the tank top, which was put over your shoulders and barely fit on your chest. The shorts slid up your legs without too much trouble. The flip flops we're put on next as your toes slid in between the divider. The final piece was the bracelet that he always wore, fitting the rubber accessory onto your right arm like he had done. Admiring yourself in his clothes, you made a couple of poses and laughed to yourself. You looked absolutely ridiculous. The time for fun was over and you began to step out of it all when your body would freeze.
Suddenly, a wave of heat pierced through your body. It felt like you were in a sauna. Wiping some sweat from your forehead, you watched as your pale skin gained a healthy tan. "What the..." You were interrupted by the sound of bones tracking and your body expanding. Slender and lanky limbs would soon burst with muscle and strength as they gained definition. Feeling so stiff, you stretched as hard as you could and flexed. Every little fiber would make itself known to you.
Hurrying to Jacob's bedroom, your looked in the mirror to see a cross of you and Jacob together. Your chest expanded and made the gray tank top fit tight as you had seen it before. This formed a tent in your pants that would grow as you gained Jacob's large cock. "Oh my god..." You stared into the mirror, blushing as you tried not too look at that obvious bulge in your pants. The flip flops soon fit better as your feet had grown and would hug the material. "I'm turning into Jacob." You said in his voice as the changes spread to your head. Your black head of hair would grow into a short style and turn blonde. Visioned darkened for a moment as your face shifted to match Jacob's.
Looking back at your new body in the mirror, thoughts would race in your head. You couldn't remember any of when you were a kid anymore. You thought that maybe there was playing dress up with your sister's clothes but you didn't have one, did you? Jacob was an only child. Not that you wanted one anyway. They were always so annoying. You were raised in a household that loved football. No! This was Jacob talking! You clutched your head as it became harder to distinguish the real thoughts from the fake ones. The battle continued for a few minutes before you blacked out on your bed.
Waking up an hour or so later, you shot straight up. What were you doing in bed? The last thing you remembered was sleeping with Jamie on the couch. Looking in the mirror at yourself, you laughed and would remember the fucking from last night. A poking sensation down below caught your attention as your hands would push down your underwear and shorts, freeing your large cock. Beginning to masturbate in front of your mirror, you grinned and would lean your head back, fully accepting your new life as Jacob.