so, some stuff:
you can get down to your undies by taking enough damage, but it's risky cause you only get fully on the undies when VERY LOW.
with the nude passcode, you can get fully nude when capturing the ball and if you have "nude" set as undies, you have to get them via the style shop by luck of it appearing to buy, and 50K credits. then it's the same as above, get damaged until low health enough and you'll be naked. alternatively, with the nudity passcode, you can simply, while in glitch city, strip your dolls by squirting them, or interacting + toggling clothes.