The 'long i' /ɑɪ/ is a 2-sound vowel that ends in a brief 'y sound' /y/.
Part 1: At the beginning of the sound, the tongue is low and touches the bottom, side teeth.
Part 2: As the jaw closes slightly, the body of the tongue moves upward until it is near the tooth ridge, similar to the position of a 'y sound' /y/. The front sides of the tongue touch the inside of the top, side teeth.
Source: https://pronuncian.com/pronounce-long-i