upside your head means: Someone being pimp… Instead of using the palm, you can use either your “upside” or your backhand. They are often used to pimp women, and sometimes they do not follow the rules. (in Community Dictionary, added by Adalberto Muñoz)

What else does upside your head mean?

  • This phrase is mostly used as an insult, or warning. It’s usually said by someone with a weapon and wants to kick you in the face because they have been insulted. (in Community Dictionary, added by Marianna Douglas)