for me personally I think I've described it before like....

you normally play a certain character on a show. you have been on this show for 27 years.

one day, someone mistypes the script and they put your characters name at the top of a script for another character.

you may or may not know immediately that this not the character you usually play. maybe they're not that different from yours. maybe they're immediately obvious not the character you play.

regardless, you have a different script. the character that you're playing has entirely different motivations, what's of speaking, character flaws, and skills. but you also only have this script after the mix up happened, and you have to act from it anyways. suddenly, all the things you'd usually say or be motivated by or deliver as a character are all different. but you still only have the one script, with the different instructions.

so you act that way because that's what you have instructions for.

translated to less of a metaphor in general for me or usually just doesn't feel like much or anything. it's like asking me what it's like to be MS paint while I'm playing a video game. maybe MS paint is minimized in the background and not taking up much resources. maybe it's totally closed out. but in that case it's not 'like' anything. that code and information and interface just isn't present or active at the moment. your computer has stored the program away until you decide to use it again.

idk does that make sense?