The characteristic sound produced by certain [Western] underground subcultures. Usually the sound is made while putting your left hand under someone's T-shirt and by making weird faces.
Origin
It is said that the origin of this yell can be found in the Greek language, the word οτε resembles Otje quite well. The Dutch prefix "-tje" has been added to make this 'a small οτε '. But untill now it is unknown where and how this characatistic sounds exactly originated.