Jeff decided it would be kind of kinky to see how his brother Jacob was developing in the downstairs department, so he entered his and his brother's cock and balls to be swapped. Jacob was only one year younger than Jeff, putting him at 15, and he was very similar to his brother. Both had dark hair and eyes and were skinny.
Jeff set the transformation to happen in one minute and he quickly got undressed to enjoy the show, posing in front of his bedroom mirror. The transformation started and he watched his six inch cock shrink to about half its size. His balls also got smaller but not by much.
"Dang, I didn't think Jacob's junk would be this much smaller!" But after saying that aloud and realizing that he was holding his little brothers junk Jeff got really turned on. His 3 inch dick gained another inch getting hard and Jeff massaged his new prick until he came all over his stomach.