Don't see this acronym in the newbie file.  Que significa, por favor?  TIA

Found the acronym in question?

Gem is a precious jewel it means something valuable.

I looked around on urban dictionary, but couldn't find anything that defined it as an acronym, only as a comparison to "jewel".  

So, I put my "dirty mind" thinking cloak on and came up with "Gastro-Enterological Money-shot".  

I've never seen it used before and I've read several hundred reviews by now.