As Ryan stroked his body continued his change into his father.
His belly became covered with hair as it pushed outward forming his dad's small gut. His legs got shorter and feet shrank, his dad was a few inches shorter than him.
His groans slowly changed from his own voice to his dad's as his face changed and grew a shadow of a beard.
His hair thinned into a partially balding head of hair as Ryan climaxed, releasing his load from his large cock and balls.
At the same time Ryan's door opened and in walked Jeremy.
"Oops, sorry dad." Jeremy said startled at seeing his own father with a pool of cum on his hairy chest.
"Close the door Jeremy!" Ryan said quickly not wanting anyone else to see. "It's me Ryan." He said starting to clean up his mess.
"What the hell happened?"
"Dad touched me and I started changing. During the transformation I had this sudden urge to jack off and I just had to! Man, this dick is hot!" Ryan replied still looking at his large member.
"well, lets change you back before someone else see ya." Jeremy said touching his brothers hairy arm.
Jeremy watched as Ryan's hair thickened on his head, while the rest of the hair on his body disappeared. His stomach retracted, reveiling his taught stomach once again. Ryan was disappointed as he watched his dick and balls shrink back to their normal size.
Ryan dressed as his transformation finished, "Well, I'm glad that's over, although I wouldn't mind having that dick again!"
"Your sick dude, that's our dad."