[Tlhingan-hol] {yIghoSDo'}?

[De'vID]

I've encountered this expression a few times, and now it appears on
the back cover of "How to Speak Klingon".

Where is it from? Is it from an episode? It's all over the place
online, but I'm wondering about the original source.

Or is it something made up by a random person, which then got
propagated throughout the Internet until it got into print? I thought
the Klingon in the book was vetted by the KLI, did it get the
go-ahead, did it sneak through, or did the authors add it to the back
cover without consulting a Klingonist?

--
De'vID