Unclear of specifics of thawed milk.?

I know i must sound like an idiot but it's my first baby. The thing is so many sites are saying so many different things and then i just read that i should go based on the smell of the milk. I have milk in the freezer. As far as thawing it i know you should run it under water or warm up water in a cup and dip the bottle/bag inside it. What if i were to just let the milk thaw out in room temp ? let's say it was a six oz container full of milk, could i take 2 oz from it and let the rest still be kinda frozen and continue to get more 2 oz portions as it thaws out ? in general i want advice on how i should thaw out and use the milk. *i do not plan to thaw it out in fridge because it takes a while and lm wondering as far as me using it let's say on a one day basis where i m out running errands or something and cannot pump or feed .