"I wish you were my boyfriend, li'l bro, able to satisfy all my little bro fantasies." you say. "And I wish you'd follow any order I give you."
Awareness flickers into your lil bro's eyes, and he begins coming onto you.
"I have another idea," he says, pulling you inside the house and closing the door behind him. "Let's fuck. Nobody's home, and I know you want to."
"Yeah!" you say, caught up in the moment of this happening.
He dashes to your older brother's old room (now his, with that brother living on campus), and you run after him. He flops onto his bed, and you cuddle up next to him. He begins taking your clothes off, then his, throwing them into loose piles around them. You're both erect, but his cock is big for his age, almost as big as yours.
"I wish your cock would magically clean and lube any ass you stick it into." you append as he greedily pulls you around to align your legs on his shoulders. "And I wish you're flexible enough to suck my dick while fucking me."
He smirks, understanding what you want done to you as he penetrates you surprisingly easily. He leans forward, playfully flicking your cock and stroking it a bit before going down. You're ecstatic, watching that little brunet guy sucking you. Your acceptably-breasted girlfriend might've pounded you great with a strap-on, but having it be a real manhood...why not have more rapidfire wishes?
"I wish you can keep fucking after you've cum, and can cum multiple times in a row whenever you want." you add as you blast a load down your brother's throat, breathy as he swallows. "And I wish that your cum makes guys able to orgasm again immediately."
A strong thrust into you followed by an increase in warmth, then another shot into your brother's mouth confirmed it was working. So, you could change your brother to make him change other people. You enjoy your combo suck-and-fuck for a while longer before...
"Hey, ride me instead." you ask, letting him pull out and mount you so you can still see his face and have easy access to his cock. "I wish your asshole is self-cleaning and tight yet easy to enter. And I wish your cum would clean up things instead of making them sticky or stained, and can meet all dietary needs if consumed. Bro, I love you."
You start jerking him off, getting a snarky "Yeah, I love you too." and a spray of cum all over your upper body for your efforts in creating your perfect fantasy fuckboy. You scoop up some with your free hand, drink, and feel satisfied. This was a great idea.
Pulling your brother forward, you hug him tight and fire off yet another load in his ass, then adjust a bit more so you can kiss him. His cleaning-cum begins evaporating, leaving the area feeling surprisingly fresh-scented and clean instead of dirty after so much sex.
"So, maybe now some videogames or TV?" you ask.
"Hell yeah." your bro says, giving you a fistbump. You take advantage of his relatively light weight to pick him up and carry him the short distance to a nearby TV, letting him adjust in your lap so that he's facing away from you now. No particular reason to pull out, not with all the cum he's producing making it easy for you to get it up again.
You turn on the TV.