Julia's burning with determination to show Adam that he cannot continue to have his way in everything.
She is hell-bent on wanting to leave Adam shaken by her skills. She wants to see him squirm and be vulnerable because of her actions.
The need to at least win something grows in her as she sees that her methods are working.
Hearing him moan for the first time as she took his cock deeper into her mouth made her realize that Adam's not inhuman. He can still fall under the influence of pleasure like every other human being on the planet.
She just needs to do a much better job and completely overwhelm Adam's senses. Nothing would make her feel happier than seeing Adam unable to control himself and ejaculate prematurely because of her skills.
For a man like Adam, who always walks around with arrogance and is full of himself, ejaculating prematurely before he can do anything else would definitely be a huge blow to his ego.
