Jon stared at the panties in horror. Even though he hadn't minded gaining breasts before, he had never wanted to wear girl's clothing. "And, what if I don't want to?" Jon asked. He knew there would be a consequence, but his morbid curiosity got the better of him.
"Are we really going to do this every time I ask you to do something?" Karyn asked. Jon nodded. Karyn snapped her fingers. "Fine. Concentrate whenever you wear clothes without panties on, your butt will expand, but if you wear panties, it will be regular sized and firm."
Jon picked up the boxers. Karyn looked like she was going to say something but ended up giving him a bemused smirk. Jon slid the boxers on. He felt movement behind him. He looked at his butt and saw it swelling against his boxers. It kept on growing and growing, until his boxers ripped and fell off.
Jon's butt was huge, especially compared with his small slim body. He tried to walk around, but it felt more like a waddle. Karyn started to laugh and Jon chuckled as well as he tried to move. "Okay," Jon said, "you win. Hand me those panties."
Karyn did so and Jon put them on. Immediately, Jon's butt returned to normal (maybe a bit more curvier). Karyn still was trying to hold back her laughter; good. Maybe her punishment won't be quite as bad if she's in a good mood. Though, he was somewhat interested in what she'd do to him if she was really angry. It was a win-win either way.
