to socialize with in public
Comes from the formal meaning of "hang out": to protrude or stick out. Hence, the use of "out" for public. Not to be confused with "hang with", which is an umbrella term that includes socializing publicly or privately.
Friend: "Dude, you never hang out with me anymore."
You: "Not true: even though I don't get out of my house much, I still socialize with you on Facebook, which can be seen by other people."
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug