Throw up yellow bile every now in then in the morning while tongue cleaning/brushing teeth, what does it mean? (24 years old)

Gag reflex. You just might be hitting a gag reflex area. These usually can cause a reflex that can make you gag and can bring bile up which skin like that's what you doing. You could have something known as gerd, or acid reflux so the acid in the stomach isnt in you stomach but in you mid chest region do its easier to come up.
Gag. You have an active gag reflex. Try not to go so far back on your tongue while cleaning it.
Be gentle brushing. It is good to brush you teeth every morning. Be careful that you don't jam your toothbrush too far down your throat. There are several causes that are not realated to your mouth and teeth so perhaps a visit to your doctor is advised.