Jacob gets involved, too

Just then, his son Jacob who was absolutely quiet up to that point started to shiver nervously. His mum looked over and noticed.
"Hey, hun, you feeling alright?" She asked.
See, Jacob was 24 and almost the complete opposite of Walter. They shared the same hair and eyes, but Jacob was overweight and somewhat of a weakling.

Jacob was out of high school, but hadn't yet pursued college. Being only interested in video games, he wasn't very social, and really didn't care about much outside of the virtual world. Though he didn't have the looks of his father, he did inherit a larger penis, measuring at 12 inches. If only he socialized with women, he'd be quite popular.
That is why what came next was no big surprise, at least to Walter. "No mom, see...." he started. And in mere seconds, the two and a half women in the room watched his junk go from normal to jumbo size! His Mother gasped.
"That's your father!" she shouted angrily.
"I know! But... I just can't control it, mom!" Jacob exclaimed desperately.