Used mainly in casual or party contexts, not in formal situations. At the house party, everyone was relaxed, laughing, and ready to throw shapes.
Pro Tip 2/3
Energetic Dance
Implies dancing with a lot of energy and possibly skill. When her favorite song came on, she couldn't resist and started to throw shapes enthusiastically.
Pro Tip 3/3
Youthful Slang
Common among young people, may be unfamiliar to older generations. My grandad was confused when I said I was throwing shapes at the club.