You carefully weigh your options... then impulsively pull down your pants and underpants, grab the green condom, and pull it over your small, partially erect cock. Then it strikes you what you are doing. The part of you that is Scott, Mark's younger brother, is trying to emul-- something-- EMULATE! your bigger brother!
You feel confused for a moment. Hadn't you wanted to go back to being your old self? But you really do love your older brother, and want to be like him, right? But he isn't really-- WHOA!
The lube kicks in, and your partial erection goes rock hard, throbbing. You grab the loose fitting rubber, and start to masturbate, forgetting everything else for the moment. Man! This one's lube is even stronger stuff than the last one!
This time it seems only scant moments before you are ejaculating.
Blinking, you look around. Yes! It seems to have worked! You're definitely taller than before!
You turn to your brother...
...and find you are still looking up at him. What?!
"So that's what it looks like," your brother finally says, seemingly more to fill the silence than anything else.
Meanwhile you are looking at yourself. You are taller, all right, but now you are really skinny, all fat gone, apparently into height, and only a little more muscle. Rail thin, twig like, is how you would describe your new self. Maybe worse yet, the condom is still loose fitting! You are still a junior high kid, still Mark's younger brother. Still a late blooming fourteen year old.
"Why didn't I turn into your twin?" you ask, shocked.
Mark shrugs.
"How would I know? Maybe each one works a little differently, maybe the magic or whatever got partly used up on me. I dunno," he admits, getting up and putting a brotherly arm around you, trying to comfort you. "You know, I just thought of something while you were, you know."
"What?"
"Our Great-Aunt Ida is into some pretty strange stuff. You know, tarot cards, Wicca gatherings, magic type stuff," he suggests, sounding thoughtful. "Maybe we should take these to her and see what she knows."
"Oh, man!" you groan, theatrically. "I don't even want to know why you thought of HER, while I was jerking off! She's gotta be AT LEAST eighty!"
Just like you hoped, Mark turns red.
"I was NOT thinking of her like THAT!" he protests.
"Pervert!" you laugh. Laughing actually makes you feel good for the first time since this whole "thing" started.
Calming down, you consider what to do next.