The way she speaks and looks at you...you know it's the way of a caring owner taking care of a pet. Yet, now you're not offended by it: her genuine acts tell you that even if she expects to have fun with you, she will also do her part of taking responsibility for your well-being. You are not certain if this will help or hinder any possibility of making her realize your true nature but either way, you can be more or less certain that you could have an excellent time, under the care of a loving, cute giant girl. 

So, in the end, you decide to trust her enough to comply finally, so...you get close and start to drink.

It takes but a few seconds, for the milk's natural thickness to make it hard to drink as a normal drink, yet the taste is undeniably good, and deep down...very special, for this is likely a very intimate experience for her.

At first, it's just a few hesitant gulps, but soon enough, you eagerly began to lick and suck with your mouth the orifice with its large enough for your whole body to fit inside: you had no idea how hungry and thirsty you were until now, and its tastes heavenly. Not to mention the fact that each of your actions sends small ripples of pleasure to Shina, who giggles at how frantic you have become. She then comments, in a happy tone:
"Yeah, that's it! So eager for my milk, aren't you? Hehe, don't worry, there is a lot for you, so don't worry of it ever running out; keep going, ahh..."

The girl then stops and begins to moan, the pleasure of your actions mounting steadily. She closes her eyes for a few seconds, just enjoying your licks and sucks before she continues, saying:
"You know, for how frantic and energetic you're moving right now, tells me that you weren't as weak as I originally thought: I'm certain that my milk is good, but not that good!...perhaps you wanted to drink while having me gently watching over you, instead of drinking it up straighter from the source, all inside me? Oh, you naughty pet, expecting to have his owner watching directly every action of his..."

Her tone combined with her grinning smile and the way she looks at you makes it clear that she's just teasing you, instead of chastising you for potential misbehavior. 

She then concludes by saying:

"Well, don't worry, your owner also likes to see you drinking like this: to hold you against my nipple, to feel each lick and suck of your tiny mouth; it might not feel as good as those same actions inside my breast, but it's good regardless. And it is...lovely, to see you as my tiny "baby", my very special and beloved pet, with only whom I can have these moments. If you want, we could make this a staple act at each meal, right? I'm certain that you would enjoy that, wouldn't you?

You're certainly not against the idea: it would allow you to feed on a more open environment, while still having a rather intimate and pleasant time with the girl. With every gulp, the idea of living under Shina's care grows that bit more appealing, all things considered. There are still many matters you would desire to correct, yet overall...your likely future under her care doesn't look that bleak after all.

It might have felt like it lasted forever, yet everything comes to an end, especially considering how small you are: it likely lasted at most a few minutes before you were full. When you stop sucking, it's a clear signal to Shina as well, who gently pulls you away to her face, where she smiles and asks:

"Hehe, all full my pet? Did you enjoy it?"

You nod in return, a reply that makes Shina blush excitedly before she speaks again, saying:

"Now, this was fun, yet I need to get up early for school tomorrow morning. However, if you feel energized enough due to the lovely meal of yours, I wouldn't mind you squirming and sucking my insides for a while more. Either well, it's time for you to return to your home, within me, your caring and loving owner." 

And with those words said, she brings you back towards her breast, where she shoves you inside her raised nipple, pushing you far before letting her internal muscles guide your ride to your "bedroom" by themselves. 

And as you find yourself tuckered out inside the mammary gland where this whole chain of events started, empty of content except for you, the idea of squirming around inside her might be a possibility, for either further "fun" with Shina or a potential escape attempt: you might grow to like her that bit more, yet you would perhaps still be interested to know the "wider world" outside your location within her. 

On the other hand, even though the milk did energize you, it might also help you sleep all the better, with a full stomach and all that. 

To conclude, will you move around for fun or escape, or prefer to return to sleep, alongside your owner?