Despite feeling that refusing will get her awake and fully focused on you, you remain still: to you, this is more than a matter of drinking milk or not; this is a matter of trust and obedience. In your mind, to obey your captor in such a trivial matter would mean submission to her will; it's not like you need to drink it to remain fit and able to please her later, being her sex toy and all that, right? Therefore, you not only see no clear downside for refusing to drink right now, but it would perhaps serve to show her that you're not a "lap dog" she can expect to comply with every one of her whims. 

Independently of your thoughts and considerations on the matter, Shina has some of her own as well, and as she fully awakes, she speaks intrigued:

"There must be something wrong with you: there is no way you would refuse such a delicious meal..."

Then, you feel how your whole world rocks as the girl turns her entire body sideways, followed by her muscles beginning to push you out: you would be happy that you get to exit your current location...if not because most likely, she's just pushing far enough so she can grab you; if that's the case, then a escape attempt would be futile.

And, as you expected, once you get your upper body out, you manage to see how a pair of gigantic fingers quickly close on you, grabbing you firmly and pulling your entire body away from her nipple.

She moves you very fast across the air until you are fully face-to-face with her face. 

Then, she began to rotate and move you sideways rather carefully, as if she was inspecting a precious faulty toy...or a beloved pet who might have some dire situation afflicting them. 

She then probes you gently with another finger, before she speaks again, now worried:

"I see what's happening here: you're too weak, and skinny. It must have been very difficult for you to attempt drinking it by yourself, right? Awnn, you poor thing..."

You feel rather offended about the conclusion the girl came out after checking you: you're rather ok, all things considered, you just didn't want to drink her milk, nothing more.

You're so offended that you want to reply to her, but before you can protest, the girl continues, smiling a bit while speaking in a calming tone:
"But don't worry my pet, your owner is a responsible individual, and I can help you feed yourself until you're fit and strong enough to do so by yourself. Here, let me show you..."

She then brings you closer to her breast again, where you're able to watch how she begins to massage and stimulate it, moaning a bit as the process brings quite some pleasure to the giantess. 

It takes but a moment before the thick white liquids begin to pour out in a little stream from her insides; once she's confident there is enough pouring out, she brings you closer still, in direct contact with her nipple, and with your head in reach of the pouring substance.

The fingers grabbing you mostly cover your chest area and below part of your body, thus allowing you to raise your head freely, enough so that you can lock sight with the girl: she's looking at you with caring eyes, clearly worried about you. In a tone matching her eyes, she concludes:

"Come on, my beloved pet, drink up, it's all yours: as I told you, you can count on my help if need be."

Deep down, something tells you that her words and actions are proof of her genuine care of you: even if she doesn't view you as the human you are, she still wants to do what she thinks is best for her "pet"...and honestly, that's rather a good thing, all things considered. She might expect you to please her when she desires, but to know that at the same time, she would worry and take as good care of you as possible, might make her worthy for you to obey her.

On the other hand, this is also further proof that she views you as lesser, something in need of care. But despite everything, you are not weak, nor incapable of fending for yourself. The fact that she believes this is the case shows that any obedience will not aid you in showing her that you're far more than the non-human tiny she thinks she has.

In the end, what are you going to do now? You got the feeling that either choice you make will have great consequences...