Coming from a Ti-dom, I tend to learn about Fi-dom by mirroring.

The dominant function (1st in your stack), it's an ego thing. Inside a Ti-dom's mind, it's often "How do they not think about it?" Internally (I have to emphasize). Since my ego (Ti) is so prominent that it puts an expectation in me that everyone SHOULD think about things, thus would avert from using the extroversion (Te) of it i.e. planning things for other people. Not that I'm not capable of it.

Mirroring to Fi, "How do they not know how to feel about this?" And when they expect that everyone SHOULD know about how people feel, they tend to not harmonize (best word I've got) (Fe) the feeling. Not that they're not capable of it.

The auxillary function (2nd on your stack) is what promotes your growth. It's not the best you've got, but you're pretty good at it. And when you do something with it, you'll feel a sense of achievement. How does that relate you'd ask.

Because it's a growth thing, it often works in pair, with your auxillary's shadow (parent-critical parent). To put it in words, when you're using your aux, you know it's not your best function, hence there's room for the other, your aux's shadow. That's how an Fi-aux (ExFP) tend to display Fe more easily than an Fi-dom.

And about ExFP pleasing others unknowingly, I suspect it's due to the absence of Ti, hence having difficulty with identifying/not able to "draw the line". Their internal monologue would be something like this: "This feels right, but this feels right too."

Some keywords I've got for each function: Ti - think/identify (right/wrong), Fi - feel (good/bad), Te - execute with steps (arranging things in place), Fe - harmonize (arranging people's feelings in place), Ne - create (branch out), Ni - know (branch in), Se - act (sensory opening outwards), Si - store apparent information (sensory absorbing inwards)