"I wish to be the pussy of my sister Zoe; that she is aware that I'm her pussy; that she and I can still communicate; and that she takes possession of the rock until I turn back." The rock flashed and grew warm in his hand, and Jon felt himself vanish as his vision went black.
When he came to, Jon felt weird. He tried flexing his muscles, and found that he could move his mouth around. He couldn't feel any teeth or tongue, but strangely could taste with his entire body. Everything felt twisted into a weird, inside out shape. He could feel Zoe's cotton panties stretched across him like a big blanket.
So, this is what it's like being a vagina thought Jon. He felt his new body start to moisten as he thought of what he would experience as his sister's most intimate part...