Blowing a raspberry ("prrrbhbhbhbhbh")

[André Vasconcelos]

As far as I am aware there isn't even an expression for this in my own language!

Basically it's this:

https://en.wikipedia.org/wiki/File:Blowing_a_raspberry.ogv

A more verbose explanation:

Blowing a raspberry, strawberry or making a Bronx cheer, is to make a noise that may signify derision, real or feigned. It may also be used in childhood phonemic play either solely by the child or by adults towards a child to encourage imitation to the delight of both parties. It is made by placing the tongue between the lips and blowing to produce a sound similar to flatulence.

The origin of the expression is quite vulgar:

Blowing a raspberry comes from the Cockney rhyming slang "raspberry tart" for "fart".

Have a nice evening!

Andre