The short version in my headcanon is ‘It varies’. Everyone’s got their own style of fluffy so you can basically set it up to be however you want. I try and write a sort of ‘neutral’ style of fluffy in general and you could take a look at these stories for how I do the backstory and in-universe stuff:
Abuser’s Web Guide Episode 2 - Fluffy Basics, Their Growth, and Product Recommendations
Abuser’s Web Guide Episode 5 - Discipline vs Punishment, Sources of Poor Behavior, and Introductory Fluffy Psychology
Abuser’s Web Guide Episode 8 - Advanced Fluffy Psychology and Herd Dynamics
Abuser’s Web Guide Episode 9 - Behavioral differences between Domestics and Ferals
Abuser’s Web Guide Episode 12 - Fluffy Neuropsychology
Abuser’s Web Guide Episode 15 - Bitch-mare syndrome
Other examples of the range of fluffy behaviors can be found in any other writings I’ve churned out so far. On one end you have characters like Lightning from my Sam and Will stories on the upper end of intelligence.
And then you have characters like Lilac, from the same series.
In the end it’s up to you, though.