طرف اللسان وأطراف الثنايا
The tip pushes out between the teeth, touching the edges of the upper front teeth, and the air passes over it. Ẓāʾ, dhāl and thāʾ are made here.
Letters made here
Common mistake
Pulling the tongue back behind the teeth, which turns thāʾ into sīn and dhāl into zāy.