The body of the tongue is relaxed and set low in the mouth. The sides of the tongue lightly touch the bottom teeth during the formation of the sound. The jaw is kept in a neutral position, and the lips are relaxed.
The overall relaxed nature of the formation of this sound is why it is commonly used for the pronunciation of the vowel sound of an unstressed syllable. The 'short i' /ɪ/ sound may also be used in an unstressed syllable, but short u /ʌ/ or schwa /ə/ are more common.