To make it,the jaw drops just a little bit. The tongue tips stays behind the bottom front teeth. The middle /front part of the tongue arches up towards the roof of the mouth , diminishing the space between the tongue and the roof of the mouth.
The corners of the lips pull a little wide, They are not quite relaxed.
When stressed, the vowel has the up-down shape of a stressed syllable,When unstressed, it’s lower and flatter in pitch, quieter, and faster