Why John Stamos’ 4-Year-Old Son Billy Calls Him “Poopy”

It seems like John Stamos‘ son Billy has developed quite the potty mouth.

The Full House alum light-heartedly lamented over his 4-year-old’s new infatuation with the word “poop,” revealing on the Oct. 12 broadcast of Live! With Kelly and Ryan that the tiny tot—who he shares with wife Caitlin McHugh—has even started slipping it into everyday conversations.

“His new thing is that he likes to say ‘poop’ all the time,” John shared, before telling Kelly Ripa and guest host Mark Consuelos that Billy frequently shouts, “‘Hi poop!'”

And when the actor tried to explain to Billy that it’s “not appropriate to say ‘poop’ in school,” the little one was quick with a cheeky response. “He said, ‘What if I go to a poop school?'” John recalled. “He’s smart.”

In fact, Billy has even used the word to troll his dad. Calling back to a FaceTime chat they recently had, John told Billy to look outside so they can see “the same moon” together, only for his son to drop the p-bomb during an otherwise “beautiful moment.”