It is hard to describe the action, so here is an example:
What is the word or phrase that best describes this noise made by a person?
If the request relates generally to the making some kind of imitative sound then mouth sound effect might be the best and most obvious choice here. The clip shows a character imitating a vampire hiss (I assume) and SFX Source has a listing of "mouth sound effects, mouth sounds" including lots of vampire hisses (along with chattering teeth, clucking, pops and so on).
Sound effect, while shorter, could also mean a variety of sounds that the mouth can't make.
Onomatopoeia -more details below http://en.wikipedia.org/wiki/Onomatopoeia