Somebody Tell Me Please...

What does it mean when someone says, "That was an HHJJ moment." ??

My nephew wrote it in his blog and used it in a positive light. In other words, he described something good that happened to him, and said it was an HHJJ moment.

Then the little shit said, "And if you don't know what HHJJ means, you're too fucking old."

Wellllllllllll, I am NOT too fucking old! I want to know what this means.

Somebody clue me in please (because I am apparently too fucking old!)