How to spell a sound I hear people make

When you stick your tongue outside of your mouth and gently blow, it makes a common sound to indicate "whatever!" or "I don't like your answer/response" or "Yes, you are smarter than I am."

What is the name of this sound and how do you spell the sound?

Solution 1:

I wonder what the linguists will make of this question.

It sounds as though you are describing what is colloquially known as 'Blowing a Rasberry'.

As to how you would represent it in writing, I'm a bit flummoxed. Experiment with the following (all as long or short as you wish);

Brthrthrthrthrth

Pthwrzrthwrzzz.....

Much better than the internet Pbbt. You could have started something here.

Solution 2:

I believe the word you are looking for is "pfft", defined as:

An expression of a lack of interest in another persons comment

Blowing a raspberry is something different, and noticeably more insulting.