Without a stone Jon wondered how he was EVER going to change back. He was stuck with his head and genitals on the body of a fat girl. Then Jon realized what Zoe said. His body changed to match that of his last sexual partner. If that is the case, until he finds what happened to the stone the only way to change back was...
Jon shuddered. He had never contemplated sex with a man before. But he couldn't think of any other way to change back.