Watch Zach Galifianakis Describe How His Son's Testicles Fit Perfectly Into His Bellybutton

The other golden ratio.

Fatherhood is full of magic moments, but there has been none so magical for Zach Galifianakis as the moment in which, while bathing with his infant son, he discovered that the universe had conspired to prove that they truly belonged together:

"I realized, when were bathing once, that his testicles fit perfectly in my bellybutton," Galifianakis told Jimmy Fallon on "The Tonight Show" Monday.

For more golden insights and sage parenting advice (including the value of "prenatal spanking"), watch the full video below.