Some things in life never get old. For males, it’s bathroom humor.

I will admit it. I’m not immune to the stuff. It can still make me laugh. It can make me laugh hard. And if all the bathroom-humor-oriented movies, books, stories and web sites out there are any indication, I am not the only adult with this weakness.

But now I have two sons. And there are times when, as their father, I really shouldn’t be laughing and pointing and nodding and even tearing up at their potty humor (namely, when at the dinner table or in public). But sometimes it’s damn tough, and I find myself forcing a straight face as I tell them to cut that out, you don’t talk about poo-poo sandwiches at the dinner table. And there are times when even my wife fails to keep from laughing at what our 3-year-old son Dylan has come up with.

Which, of course, causes Dylan to beam with pride — fortified by the laughter of his audience — as he resolves to dive deeper into his potty-humor repertoire.

For Dylan these days, songs, monologues, jokes and games centered around “poo and privates,” as he calls his subject matter, never lose their luster. He just can’t get enough. Case in point: This weekend, the boys were wondering how many days have passed since they’ve been born. I worked out the math, and they were fascinated. Then Jack wondered how many days have passed since “prehistoric bugs” roamed the earth and even offered his best guess: “Three million, two hundred, fourteen-thousand, twenty-five trillion and seventy-two katrillion days.”

I turned to Dylan. “And what’s your guess?”

Dylan takes a deep breath. “I think its been two-four-ten pee-pee-pillion, one diarrhea-rillion and one poo-poo-pillion days.”

I stared at him and bit my lip, fighting the urge to grin, thinking, Ah, to be three again.