Can be used to refer to an object or person, i.e: "Pass me that shang" or "Shang was telling me..."
Can also be used to communicateenthusiasm, perhaps as a less effeminate form of "slay": "You shanged that!" or "he shangin"
"he shanged me" could mean "he ripped me off"
Honestly it doesn't really mean anything, you can use it however you like and it's entirely dependent on context
"that shit shangin" could mean it's amazing or terrible