In fanfiction, Tim Drake whimpering can be a powerful device for character development. It might be the starting point for his growth. For instance, he could start as a whimpering mess in a situation but then find the strength within himself to overcome it. This transformation can be very engaging for readers and make the fanfiction more interesting.
One possible fanfiction could be about Tim Drake in a difficult situation, perhaps trapped or facing a great danger, which makes him whimper. This could show his vulnerability and human side that is not always seen when he's in his heroic role.
In a Giyuu x Shinobu fanfic, the setting and plot can vary widely. Some might be set during the main events of the Demon Slayer universe, with them facing demons together. Others could be more of an alternate universe story, where they meet under different circumstances, like in a modern - day high school AU. The fanfic could also delve into their backstories and how those experiences shape their relationship. For instance, Shinobu's past with her sister could play a role in how she opens up to Giyuu, and vice versa for Giyuu's own traumas.
I would recommend 'Whispers of the Heart' for Giyuu x Shinobu fans. This fanfic focuses on their unspoken understanding. It's full of small moments that build up their relationship, like when Shinobu leaves a small flower on Giyuu's doorstep as a sign of her care. Also, 'Shadows and Sunlight' is worth checking out. It has a great plot that involves them having to go on a secret mission together and how that journey changes their relationship from colleagues to something more intimate.
One common theme is the exploration of their relationship. Given their different personalities in the original work, fanfictions often focus on how they bridge the gap between them, like how Giyuu's stoicism and Shinobu's more cheerful yet calculating nature interact.
One reason could be that it senses danger nearby. Arcanine has strong instincts. If there is a hidden threat like a sneaky and powerful enemy Pokemon approaching, it might whimper to alert its trainer or just because it's a bit afraid.