Abbreviation of "Poggers" originally developed by weebs/hentai dumbfucks, it is now a common expression among gamers to signify that a situation is desirable or the outcome is pretty cool.
Person 1: "LET'S GOOO FINAL KILL!"
Person 2: "Very pog bro."
After attending online classes for 8 of your 24 hour day, and your bitch professors decide to assign you 30 hours worth of homework due tomorrow: "Unpog, this is not epic, I'm gonna go eat a bullet now."