Definitions by The birds are coming

Bird purring 

Bird purring is a sound made by humans and is rarely heard in the wild. The technique one must master to create this sound is known only by a few, but the legends say it's similar to the sharp Norwegian R. Bird purring is used for many things, such as avoiding silence, asserting dominance, letting your presence be known and show emotions like happiness and confusion.

Yesterday I showed my friends one of my projects, their positive responses made me bird purr in happiness

Friend: Wow! You did really good!
Me: *Bird purring*

Bird purring by The birds are coming May 15, 2020