Blowing a raspberry or strawberry or making a Bronx cheer is to make a noise signifying derision (and/or silliness), made by sticking out the tongue between the lips and blowing to make a sound reminiscent of flatulence. In the terminology of phonetics, this sound can be described as an unvoiced linguolabial trill. It is never used in human language phonemically (i.e., to be used as a building block of words), but it is widely used across human cultures.
