Can be used in conversation when you are just about to tell someone something and then decide to not tell them so once you say "dwa" it stops them going on about it and whining to you about it.
It's like a counteract to Tealeaf
Hollie: oh hey guess what..
Kari: what what?
Hollie: oh wait no dwa
Used in conversation when somebody mentions something you want to know but then says "dont worry" and wont tell you. Once you have shouted "tealeaf!" the person must tell you straight away what they were going to say.