Maybe more quasiphysical? Like for example, even in his human form, Bast in headspace is Large, so when he's at front there's this weird sense of... being bigger than our body actually is?
It's really hard to describe, but it's almost kind of if your sense of self was overflowing past the bounds of your fleshy vessel and you can almost feel the body that you internally have instead. Non-plural otherkin/therians/alterhuman folks also often experience something like this.
There's also some more subtle things. When Bast is at front, our body also feels more solidly rooted to the earth - we're aware of our weight upon our feet upon our ground. When Lark is at front, our body tends to be more... light? Like before, these are more shifts of perception than actual physical sensations, though.
We do get some more physical feelings, like our face going numb for a moment or our arms feeling heavy, but they usually crop up in the transition between fronters and pass whenever someone gets settled at front. There's also perception differences like some headmates having more tolerance for pain, some foods tasting different, and so on.
I hope that gets at what you mean. If there's any specific flavor of physical sensation that you're curious about, feel free to send another ask.
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