I keep forgetting.

...then remember what, exactly?

That you are stuck in a physical form that doesn't allow for a basic movement that you feel you should naturally be able to do.

Mmm, okay, fair enough. Personally I don't often get it much in the sense of "okay, I will do this normal thing ... ohhh yeah no wait I can't" but I guess by now I'm pretty used to what "normal things" I can't actually do, so I rarely "try" in the first place.

I think they mean remember that in our human form, we don't have a wings or tail.

I occasionally get the itch to do so and roll my shoulders back as if I'm unfurling wings. I don't feel anything, but it's nice to close my eyes and imagine sometimes.

I'm very familiar with the crippling feeling of not having a physical connection to that which i can still feel otherwise. It pains me every time it happens to know they're only there as part of my astral form