It's been around a week already since you decided to try fulfilling your "job" as Shina's pet: it's something she would appreciate the most, even though it makes it very hard to show any signs that might hint to her of your true status.
Regardless of that drawback, it soon proves to be a rather pleasant experience: she proves to be a rather gentle girl, demanding only for you to squirm around inside of her when she wants you to, with no further expectations of making her climax once or several times at each playtime you have (although she appreciates them when you manage to provoke them).
The routine quickly grows on you: during the mornings of the first days (which by proxy tells you she found you on a Monday), she goes to school, where you often end up waking up; at those times, she's never eager to play with you at school, even on the breaks, something you don't mind since this means more time to just relax and enjoy your naps inside her.
It's during the afternoons when playtime comes around: she loves to take a cup of coffee while feeling you moving inside her while having always her trusted change of clothes ready at hand if things get heated. You can't help by be impressed by how much control she has over her reactions, never moaning too loudly or twitching in a manner that might gain the attention of others. Combined with the fact that you can hear and to an extent feel how she cleans any mess you might provoke in a very thorough and practiced manner, makes you wonder if she's previous experience...
Yet you don't have enough time to linger on such thoughts for long, for your efforts always end up with you utterly exhausted or willingly crawling up to sleep, a necessity on most occasions since soon enough at her home, she loves to feel you squirming and making her enjoy an excellent time before dinner. It's in the privacy of her home where she's most relaxed, being able to just close her eyes and focus on the pleasure of your licks and caresses inside her breast while ignoring everything else. Or it would be the case, hadn't she not enjoyed pulling you and squeezing you from time to time: she gets rather turned on with how much power she has over you.
You never get mad at her: sure, it makes your efforts to pleasure her more challenging than perhaps needed, but that extra challenge was beneficial in training you in how best to keep up squirming and wriggling despite the size difference. It also serves to further develop your stamina, with Shina surely appreciating being able to have you squirming around for longer periods than before. And, it serves as a constant exercise regarding any effort in getting out, should you one day desire so.
For the moment, however, its biggest impact is allowing you to become better able to reach her G-spot, no matter how often or how hard she pulled or squeezed your tiny frame within her breast. And each time you manage to reach it, you nearly certainly manage to make her climax, with predictable results. Yet Shina never got panicked each time this happened, since you always chose to remain where you landed, ready to be picked up and return inside her.
Yet despite the "training" you underwent, each attempt of yours was tough and exhaustive, never being able to move around in such a hot, air-stagnant environment for longer than a few minutes. Hence, each playtime always ends up with you utterly expended yet happy.
Lastly, while Shina slept soundly for the rest of the night, you often woke on your own. Even though you could try to have further fun with her, you are aware that this would likely impact her performance (no matter how much she would likely enjoy feeling you squirming out of your initiative), so you prefer to quickly follow her suit, taking the advance of taking a deep slumber to recover all the spent energies of the day, mulling a bit about your next goal for tomorrow.
This basic routine quickly becomes more developed, for on the night of the second day after choosing to remain with her (around Thursday more or less), after dinner and before bed, she pulled you out to have a nice conversation.
This conversation was soon followed by others the next night. All of them proved to be rather fun and interesting: through them, you learned more about your "owner", how her day had gone beyond your playtimes, and more importantly, how girls are expected to interact with tinies; they are seen either as living sex toy or treats, squirming and struggling one way or another for the enjoyment of their owners. They are overall disposable, and thus there is no need to take good care of them (unless you want to make them last instead of searching for a replacement), for even though extremely rare, the chance of catching a tiny is beyond negligible.
A cold shiver ran down your spine when you learned of this: the thought of having been caught by a cruel girl who would truly abuse you or worse, eat you at the first try were scenarios worth of nightmares. If you had doubts about the wisdom of remaining with Shina, now you were certain it had been the better choice.
Overall, this basic routine remained more or less stable for the rest of the week: remaining still in the morning, playing during the afternoons and nights, and chatting before sleeping. And with each session of "games" and chats, you two grow closer, to the point at the end of the week where Shina, instead of asking you to play with her before dinner once she arrived at her home, immediately pulled you out, and while grinning, she talked to you, saying:
"Hehe, you know, you've been such a good and obedient pet! Therefore, I believe a reward for such diligent behavior is necessary. And, to make it even better, I will let you decide! Yes, you get to choose what reward you would like to receive, isn't that awesome? Just think a bit, and then tell me, I promise to provide the gift you want, unless it's something too crazy, hehe!"
Well, your loyal conduct has paid off, allowing you to ask Shina to give you something as a reward.
The main question is, what could you ask your giantess owner that you as her tiny would appreciate receiving?