It is pronoumced by raising the tongue tip against the upper teethridge to block the air and then putting it down to release the air.

下唇接触，形成一条狭缝，气流狭缝中磨擦而出。

It is pronounced by raising the tongue tip against the upper teethridge to block the air and then putting it down to release the air.

舌尖顶龈，阴气流，然后移下舌尖，放出气流。