An expression derived from the Guster song of the same name, "happy frappy" is a term mixing joy and frothy beverages. If you are happy frappy, you are feeling very well, and are most likely indulging in something delicious.
"I'm happy frappy! I drink Starbucks because I'm a consumer whore! Mmmm, coffee! YAY!"
by Kefanii September 10, 2004