“Do you suppose she waited to long?” Jen asked.
“And got both?” Sam added. “Maybe... I guess I need to give her a dare as well.”
“After you switch genders, give your new penis a good wanking.”
“You’re such a perv!” Jen accused.
“I think that did it...” Cassie said in an ever deepening voice.
Reddish stubble similar to the brilliant hair that hung from her head began to grow on her face and neck. Her chest gradually flattened and her shoulders became more square. Her entire body seemed to lengthen by a few inches as muscular changes became apparent on her arms and hands. They guessed that similar things were taking place below the table. Her face shifted into a more masculine structure and finally, an Adams apple popped out a few inches up her neck.
“Wow...” He said, “I’m a guy...”
“Your bro is pretty hansom Jen.” Sam joked.
Before Jen could reply, Cassie jumped up and began to undo the skirt that now looked loose on his narrower waist. It fell, revealing a throbbing erection jammed against his panties. He quickly pulled them down and began to stroke the twitching penis.
Jen couldn’t help watching; it presented a strange mix of disgust and arousal. This boy was giving her a free show, yet she knew that it was actually her sister inside that body. Sam seemed to be enjoying it as well. One of her hands rubbed her breasts while the other inched downward.
Jen’s arousal built and she decided to take Sam upstairs to have a little fun. She almost felt bad that Cassie would be left out, but there was no way in hell she’d have a threesome with her own sister. She stood up and tapped Sam’s shoulder. With her attention, she whispered a suggestion. Sam’s eyes went wide. Without a word, the two of them slipped out, leaving Cassie to masturbate alone...
“You sure it’s OK to leave her... Or him, like that?” Sam asked as they went up the stairs.
“She... Uh... I mean... He’ll be fine... I’m not even sure he realized we stepped out.” Jen replied.
Before they even made it to the base of the stairs, Sam’s cocks managed to slip free of her labia and pushed out on either side of her panties. She walked slightly bowlegged as they rubbed against her skirt and legs. Arousal increased with every step.
“Hey, I couldn’t quite hear you in there...” She teased. “What was it you wanted to do again?”
Jen pushed her up the stairs, “Just hurry up, before I change my mind...”