Used to being her

"You've got to swap us back! I've got friends coming over," Alex begged, tossing his sister's long blonde hair out of his eyes.
Krista looked up at him confidently from within his own body. "Well, I've got Rich coming over. Now you can stand there arguing or you can get dressed, because he'll be here any minute. Though I'm sure he wouldn't mind seeing you in that outfit," she smirked.
Alex smacked the bed in impotent rage. "What the fuck do you want me to do?."
Krista repositioned herself, hand landing softly on the bulge beneath her pants. "You're much better with people than I am. I want you to make Rich my boyfriend. And until you do that I'm keeping your body."
Alex stomped off, hating every motion of his sister's body from the swaying hips to the bouncing breasts to the hair that was constantly getting in his eyes. Of all the people in the family who could have got the body swapping gene why did it have to be her? She wanted to lay about while Alex did all the hard work and then she'd jump back in for the fun part.
It wasn't the first time she'd swapped their bodies so he would have to live her life. There had been numerous tests she hadn't studied for and events she didn't want to go to. He was almost as used to being her as he was being himself.

A magical board game forces a son to swap bodies with his stepmom in Game Changer, on Smashwords or Amazon. Preview here.